diff --git a/Source/cmGlobalVisualStudio9Generator.cxx b/Source/cmGlobalVisualStudio9Generator.cxx
index 0c37b7b29..9899f9c0e 100644
--- a/Source/cmGlobalVisualStudio9Generator.cxx
+++ b/Source/cmGlobalVisualStudio9Generator.cxx
@@ -27,6 +27,11 @@ cmGlobalVisualStudio9Generator::cmGlobalVisualStudio9Generator()
   this->FindMakeProgramFile = "CMakeVS9FindMake.cmake";
 }
 
+//----------------------------------------------------------------------------
+void cmGlobalVisualStudio9Generator::AddPlatformDefinitions(cmMakefile* mf)
+{
+  mf->AddDefinition("MSVC90", "1");
+}
 
 void cmGlobalVisualStudio9Generator::WriteSLNHeader(std::ostream& fout)
 {
diff --git a/Source/cmGlobalVisualStudio9Generator.h b/Source/cmGlobalVisualStudio9Generator.h
index 03c422a6f..66d01806f 100644
--- a/Source/cmGlobalVisualStudio9Generator.h
+++ b/Source/cmGlobalVisualStudio9Generator.h
@@ -37,7 +37,8 @@ public:
   virtual const char* GetName() const {
     return cmGlobalVisualStudio9Generator::GetActualName();}
   static const char* GetActualName() {return "Visual Studio 9 2008";}
-
+  virtual void AddPlatformDefinitions(cmMakefile* mf);
+  
   /** Get the documentation entry for this generator.  */
   virtual void GetDocumentation(cmDocumentationEntry& entry) const;