diff --git a/Source/cmCacheManager.cxx b/Source/cmCacheManager.cxx
index c8374db3f..ab0bb79b5 100644
--- a/Source/cmCacheManager.cxx
+++ b/Source/cmCacheManager.cxx
@@ -849,7 +849,8 @@ void cmCacheManager::CacheEntry::SetProperty(const char* prop,
 
 //----------------------------------------------------------------------------
 void cmCacheManager::CacheEntry::AppendProperty(const char* prop,
-                                                const char* value)
+                                                const char* value,
+                                                bool asString)
 {
   if(strcmp(prop, "TYPE") == 0)
     {
@@ -859,7 +860,7 @@ void cmCacheManager::CacheEntry::AppendProperty(const char* prop,
     {
     if(value)
       {
-      if(!this->Value.empty() && *value)
+      if(!this->Value.empty() && *value && !asString)
         {
         this->Value += ";";
         }
@@ -868,7 +869,7 @@ void cmCacheManager::CacheEntry::AppendProperty(const char* prop,
     }
   else
     {
-    this->Properties.AppendProperty(prop, value, cmProperty::CACHE);
+    this->Properties.AppendProperty(prop, value, cmProperty::CACHE, asString);
     }
 }
 
@@ -893,11 +894,12 @@ void cmCacheManager::CacheIterator::SetProperty(const char* p, const char* v)
 
 //----------------------------------------------------------------------------
 void cmCacheManager::CacheIterator::AppendProperty(const char* p,
-                                                   const char* v)
+                                                   const char* v,
+                                                   bool asString)
 {
   if(!this->IsAtEnd())
     {
-    this->GetEntry().AppendProperty(p, v);
+    this->GetEntry().AppendProperty(p, v, asString);
     }
 }
 
diff --git a/Source/cmCacheManager.h b/Source/cmCacheManager.h
index 314017bf5..9c94d214c 100644
--- a/Source/cmCacheManager.h
+++ b/Source/cmCacheManager.h
@@ -41,7 +41,8 @@ private:
     cmPropertyMap Properties;
     const char* GetProperty(const char*) const;
     void SetProperty(const char* property, const char* value);
-    void AppendProperty(const char* property, const char* value);
+    void AppendProperty(const char* property, const char* value,
+                        bool asString=false);
     bool Initialized;
     CacheEntry() : Value(""), Type(UNINITIALIZED), Initialized(false)
       {}
@@ -61,7 +62,8 @@ public:
     bool GetPropertyAsBool(const char*) const ;
     bool PropertyExists(const char*) const;
     void SetProperty(const char* property, const char* value);
-    void AppendProperty(const char* property, const char* value);
+    void AppendProperty(const char* property, const char* value,
+                        bool asString=false);
     void SetProperty(const char* property, bool value);
     const char* GetValue() const { return this->GetEntry().Value.c_str(); }
     bool GetValueAsBool() const;
diff --git a/Source/cmMakefile.cxx b/Source/cmMakefile.cxx
index 63bf03bdd..e2151158b 100644
--- a/Source/cmMakefile.cxx
+++ b/Source/cmMakefile.cxx
@@ -3332,7 +3332,8 @@ void cmMakefile::SetProperty(const char* prop, const char* value)
   this->Properties.SetProperty(prop,value,cmProperty::DIRECTORY);
 }
 
-void cmMakefile::AppendProperty(const char* prop, const char* value)
+void cmMakefile::AppendProperty(const char* prop, const char* value,
+                                bool asString)
 {
   if (!prop)
     {
@@ -3365,7 +3366,7 @@ void cmMakefile::AppendProperty(const char* prop, const char* value)
     return;
     }
 
-  this->Properties.AppendProperty(prop,value,cmProperty::DIRECTORY);
+  this->Properties.AppendProperty(prop,value,cmProperty::DIRECTORY,asString);
 }
 
 const char *cmMakefile::GetPropertyOrDefinition(const char* prop)
diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 1c1aef3c0..c01bb5d8a 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -799,7 +799,7 @@ public:
 
   ///! Set/Get a property of this directory 
   void SetProperty(const char *prop, const char *value);
-  void AppendProperty(const char *prop, const char *value);
+  void AppendProperty(const char *prop, const char *value,bool asString=false);
   const char *GetProperty(const char *prop);
   const char *GetPropertyOrDefinition(const char *prop);
   const char *GetProperty(const char *prop, cmProperty::ScopeType scope);
diff --git a/Source/cmProperty.cxx b/Source/cmProperty.cxx
index 166bd007e..3b37cf3b8 100644
--- a/Source/cmProperty.cxx
+++ b/Source/cmProperty.cxx
@@ -19,10 +19,10 @@ void cmProperty::Set(const char *name, const char *value)
   this->ValueHasBeenSet = true;
 }
 
-void cmProperty::Append(const char *name, const char *value)
+void cmProperty::Append(const char *name, const char *value, bool asString)
 {
   this->Name = name;
-  if(!this->Value.empty() && *value)
+  if(!this->Value.empty() && *value && !asString)
     {
     this->Value += ";";
     }
diff --git a/Source/cmProperty.h b/Source/cmProperty.h
index 71bd1e768..e0fcd631e 100644
--- a/Source/cmProperty.h
+++ b/Source/cmProperty.h
@@ -24,7 +24,7 @@ public:
   void Set(const char *name, const char *value);
 
   // append to this property
-  void Append(const char *name, const char *value);
+  void Append(const char *name, const char *value, bool asString = false);
 
   // get the value
   const char *GetValue() const;
diff --git a/Source/cmPropertyMap.cxx b/Source/cmPropertyMap.cxx
index 052b811f9..a4d0bf3d8 100644
--- a/Source/cmPropertyMap.cxx
+++ b/Source/cmPropertyMap.cxx
@@ -59,7 +59,7 @@ void cmPropertyMap::SetProperty(const char *name, const char *value,
 }
 
 void cmPropertyMap::AppendProperty(const char* name, const char* value,
-                                   cmProperty::ScopeType scope)
+                                   cmProperty::ScopeType scope, bool asString)
 {
   // Skip if nothing to append.
   if(!name || !value || !*value)
@@ -81,7 +81,7 @@ void cmPropertyMap::AppendProperty(const char* name, const char* value,
 #endif
 
   cmProperty *prop = this->GetOrCreateProperty(name);
-  prop->Append(name,value);
+  prop->Append(name,value,asString);
 }
 
 const char *cmPropertyMap
diff --git a/Source/cmPropertyMap.h b/Source/cmPropertyMap.h
index 02fb0606a..94275e2ac 100644
--- a/Source/cmPropertyMap.h
+++ b/Source/cmPropertyMap.h
@@ -25,7 +25,7 @@ public:
                    cmProperty::ScopeType scope);
 
   void AppendProperty(const char* name, const char* value,
-                      cmProperty::ScopeType scope);
+                      cmProperty::ScopeType scope, bool asString=false);
 
   const char *GetPropertyValue(const char *name, 
                                cmProperty::ScopeType scope,
diff --git a/Source/cmSetPropertyCommand.cxx b/Source/cmSetPropertyCommand.cxx
index 3a4773ce5..cc10840fd 100644
--- a/Source/cmSetPropertyCommand.cxx
+++ b/Source/cmSetPropertyCommand.cxx
@@ -20,6 +20,7 @@
 cmSetPropertyCommand::cmSetPropertyCommand()
 {
   this->AppendMode = false;
+  this->AppendAsString = false;
   this->Remove = true;
 }
 
@@ -83,6 +84,13 @@ bool cmSetPropertyCommand
       {
       doing = DoingNone;
       this->AppendMode = true;
+      this->AppendAsString = false;
+      }
+    else if(*arg == "APPEND_STRING")
+      {
+      doing = DoingNone;
+      this->AppendMode = true;
+      this->AppendAsString = true;
       }
     else if(doing == DoingNames)
       {
@@ -152,7 +160,7 @@ bool cmSetPropertyCommand::HandleGlobalMode()
     }
   if(this->AppendMode)
     {
-    cm->AppendProperty(name, value);
+    cm->AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
@@ -218,7 +226,7 @@ bool cmSetPropertyCommand::HandleDirectoryMode()
     }
   if(this->AppendMode)
     {
-    mf->AppendProperty(name, value);
+    mf->AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
@@ -266,7 +274,7 @@ bool cmSetPropertyCommand::HandleTarget(cmTarget* target)
     }
   if(this->AppendMode)
     {
-    target->AppendProperty(name, value);
+    target->AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
@@ -317,7 +325,7 @@ bool cmSetPropertyCommand::HandleSource(cmSourceFile* sf)
 
   if(this->AppendMode)
     {
-    sf->AppendProperty(name, value);
+    sf->AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
@@ -377,7 +385,7 @@ bool cmSetPropertyCommand::HandleTest(cmTest* test)
     }
   if(this->AppendMode)
     {
-    test->AppendProperty(name, value);
+    test->AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
@@ -464,7 +472,7 @@ bool cmSetPropertyCommand::HandleCacheEntry(cmCacheManager::CacheIterator& it)
     }
   if(this->AppendMode)
     {
-    it.AppendProperty(name, value);
+    it.AppendProperty(name, value, this->AppendAsString);
     }
   else
     {
diff --git a/Source/cmSetPropertyCommand.h b/Source/cmSetPropertyCommand.h
index c477bb73b..3a0169ed6 100644
--- a/Source/cmSetPropertyCommand.h
+++ b/Source/cmSetPropertyCommand.h
@@ -56,7 +56,7 @@ public:
         "                SOURCE    [src1 [src2 ...]]       |\n"
         "                TEST      [test1 [test2 ...]]     |\n"
         "                CACHE     [entry1 [entry2 ...]]>\n"
-        "               [APPEND]\n"
+        "               [APPEND] [APPEND_STRING]\n"
         "               PROPERTY <name> [value1 [value2 ...]])\n"
         "Set one property on zero or more objects of a scope.  "
         "The first argument determines the scope in which the property "
@@ -77,6 +77,9 @@ public:
         "list.  "
         "If the APPEND option is given the list is appended to any "
         "existing property value."
+        "If the APPEND_STRING option is given the string is append to any "
+        "existing property value as string, i.e. it results in a longer "
+        "string and not a list of strings."
         ;
     }
 
@@ -93,6 +96,7 @@ private:
   std::string PropertyValue;
   bool Remove;
   bool AppendMode;
+  bool AppendAsString;
 
   // Implementation of each property type.
   bool HandleGlobalMode();
diff --git a/Source/cmSourceFile.cxx b/Source/cmSourceFile.cxx
index 42d3f06ff..dfa2c0b3f 100644
--- a/Source/cmSourceFile.cxx
+++ b/Source/cmSourceFile.cxx
@@ -291,13 +291,15 @@ void cmSourceFile::SetProperty(const char* prop, const char* value)
 }
 
 //----------------------------------------------------------------------------
-void cmSourceFile::AppendProperty(const char* prop, const char* value)
+void cmSourceFile::AppendProperty(const char* prop, const char* value,
+                                  bool asString)
 {
   if (!prop)
     {
     return;
     }
-  this->Properties.AppendProperty(prop, value, cmProperty::SOURCE_FILE);
+  this->Properties.AppendProperty(prop, value, cmProperty::SOURCE_FILE,
+                                  asString);
 }
 
 //----------------------------------------------------------------------------
diff --git a/Source/cmSourceFile.h b/Source/cmSourceFile.h
index 2dc848815..55147e192 100644
--- a/Source/cmSourceFile.h
+++ b/Source/cmSourceFile.h
@@ -44,7 +44,7 @@ public:
 
   ///! Set/Get a property of this source file
   void SetProperty(const char *prop, const char *value);
-  void AppendProperty(const char* prop, const char* value);
+  void AppendProperty(const char* prop, const char* value,bool asString=false);
   const char *GetProperty(const char *prop) const;
   bool GetPropertyAsBool(const char *prop) const;
 
diff --git a/Source/cmTarget.cxx b/Source/cmTarget.cxx
index 52b907217..191de3851 100644
--- a/Source/cmTarget.cxx
+++ b/Source/cmTarget.cxx
@@ -2191,13 +2191,14 @@ void cmTarget::SetProperty(const char* prop, const char* value)
 }
 
 //----------------------------------------------------------------------------
-void cmTarget::AppendProperty(const char* prop, const char* value)
+void cmTarget::AppendProperty(const char* prop, const char* value,
+                              bool asString)
 {
   if (!prop)
     {
     return;
     }
-  this->Properties.AppendProperty(prop, value, cmProperty::TARGET);
+  this->Properties.AppendProperty(prop, value, cmProperty::TARGET, asString);
   this->MaybeInvalidatePropertyCache(prop);
 }
 
diff --git a/Source/cmTarget.h b/Source/cmTarget.h
index 3b1f016a6..6f5dac813 100644
--- a/Source/cmTarget.h
+++ b/Source/cmTarget.h
@@ -224,7 +224,7 @@ public:
 
   ///! Set/Get a property of this target file
   void SetProperty(const char *prop, const char *value);
-  void AppendProperty(const char* prop, const char* value);
+  void AppendProperty(const char* prop, const char* value,bool asString=false);
   const char *GetProperty(const char *prop);
   const char *GetProperty(const char *prop, cmProperty::ScopeType scope);
   bool GetPropertyAsBool(const char *prop);
diff --git a/Source/cmTest.cxx b/Source/cmTest.cxx
index c25a8b6bf..502c1740d 100644
--- a/Source/cmTest.cxx
+++ b/Source/cmTest.cxx
@@ -84,13 +84,13 @@ void cmTest::SetProperty(const char* prop, const char* value)
 }
 
 //----------------------------------------------------------------------------
-void cmTest::AppendProperty(const char* prop, const char* value)
+void cmTest::AppendProperty(const char* prop, const char* value, bool asString)
 {
   if (!prop)
     {
     return;
     }
-  this->Properties.AppendProperty(prop, value, cmProperty::TEST);
+  this->Properties.AppendProperty(prop, value, cmProperty::TEST, asString);
 }
 
 //----------------------------------------------------------------------------
diff --git a/Source/cmTest.h b/Source/cmTest.h
index e27a24eaf..6223a01ea 100644
--- a/Source/cmTest.h
+++ b/Source/cmTest.h
@@ -47,7 +47,7 @@ public:
 
   ///! Set/Get a property of this source file
   void SetProperty(const char *prop, const char *value);
-  void AppendProperty(const char* prop, const char* value);
+  void AppendProperty(const char* prop, const char* value,bool asString=false);
   const char *GetProperty(const char *prop) const;
   bool GetPropertyAsBool(const char *prop) const;
   cmPropertyMap &GetProperties() { return this->Properties; };
diff --git a/Source/cmake.cxx b/Source/cmake.cxx
index 45927cb04..e5cc1a699 100644
--- a/Source/cmake.cxx
+++ b/Source/cmake.cxx
@@ -3536,7 +3536,7 @@ void cmake::SetProperty(const char* prop, const char* value)
   this->Properties.SetProperty(prop, value, cmProperty::GLOBAL);
 }
 
-void cmake::AppendProperty(const char* prop, const char* value)
+void cmake::AppendProperty(const char* prop, const char* value, bool asString)
 {
   if (!prop)
     {
@@ -3549,7 +3549,7 @@ void cmake::AppendProperty(const char* prop, const char* value)
     this->DebugConfigs.clear();
     }
 
-  this->Properties.AppendProperty(prop, value, cmProperty::GLOBAL);
+  this->Properties.AppendProperty(prop, value, cmProperty::GLOBAL, asString);
 }
 
 const char *cmake::GetProperty(const char* prop)
diff --git a/Source/cmake.h b/Source/cmake.h
index fac86c18e..b791b7c28 100644
--- a/Source/cmake.h
+++ b/Source/cmake.h
@@ -263,7 +263,7 @@ class cmake
 
   ///! Set/Get a property of this target file
   void SetProperty(const char *prop, const char *value);
-  void AppendProperty(const char *prop, const char *value);
+  void AppendProperty(const char *prop, const char *value,bool asString=false);
   const char *GetProperty(const char *prop);
   const char *GetProperty(const char *prop, cmProperty::ScopeType scope);
   bool GetPropertyAsBool(const char *prop);
diff --git a/Tests/Properties/CMakeLists.txt b/Tests/Properties/CMakeLists.txt
index e0c752297..c1bc3b9e3 100644
--- a/Tests/Properties/CMakeLists.txt
+++ b/Tests/Properties/CMakeLists.txt
@@ -71,6 +71,24 @@ if (NOT TARGETRESULT)
       "Error: target result is TARGETRESULT=${TARGETRESULT}")
 endif (NOT TARGETRESULT)
 
+# test APPEND and APPEND_STRING set_property()
+set_property(TARGET Properties PROPERTY FOO foo)
+set_property(TARGET Properties PROPERTY BAR bar)
+set_property(TARGET Properties APPEND PROPERTY FOO 123)
+set_property(TARGET Properties APPEND_STRING PROPERTY BAR 456)
+
+get_property(APPEND_RESULT TARGET Properties PROPERTY FOO)
+if (NOT "${APPEND_RESULT}" STREQUAL "foo;123")
+    message(SEND_ERROR
+      "Error: target result is APPEND_RESULT=${APPEND_RESULT}")
+endif ()
+
+get_property(APPEND_STRING_RESULT TARGET Properties PROPERTY BAR)
+if (NOT "${APPEND_STRING_RESULT}" STREQUAL "bar456")
+    message(SEND_ERROR
+      "Error: target result is APPEND_STRING_RESULT=${APPEND_STRING_RESULT}")
+endif ()
+
 # test get_property SET
 get_property(TARGETRESULT TARGET Properties PROPERTY TARGETTEST SET)
 if (NOT TARGETRESULT)