diff --git a/lib/redmine/safe_attributes.rb b/lib/redmine/safe_attributes.rb
index 6f87a233..8c49a437 100644
--- a/lib/redmine/safe_attributes.rb
+++ b/lib/redmine/safe_attributes.rb
@@ -31,14 +31,19 @@ module Redmine
       def safe_attributes(*args)
         @safe_attributes ||= []
         if args.empty?
-          @safe_attributes
+          if superclass < Redmine::SafeAttributes
+            superclass.safe_attributes + @safe_attributes
+          else
+            @safe_attributes
+          end
         else
           options = args.last.is_a?(Hash) ? args.pop : {}
           @safe_attributes << [args, options]
+          safe_attributes
         end
       end
     end
-    
+
     # Returns an array that can be safely set by user or current user
     #
     # Example:
diff --git a/test/unit/lib/redmine/safe_attributes_test.rb b/test/unit/lib/redmine/safe_attributes_test.rb
index 9498a438..bfad6606 100644
--- a/test/unit/lib/redmine/safe_attributes_test.rb
+++ b/test/unit/lib/redmine/safe_attributes_test.rb
@@ -35,11 +35,16 @@ class Redmine::SafeAttributesTest < ActiveSupport::TestCase
   end
   
   class Book < Base
-    attr_accessor :title
+    attr_accessor :title, :isbn
     include Redmine::SafeAttributes
     safe_attributes :title
   end
   
+
+  class PublishedBook < Book
+    safe_attributes :isbn
+  end
+
   def test_safe_attribute_names
     p = Person.new
     assert_equal ['firstname', 'lastname'], p.safe_attribute_names(User.anonymous)
@@ -84,4 +89,18 @@ class Redmine::SafeAttributesTest < ActiveSupport::TestCase
     assert_equal 'Smith', p.lastname
     assert_equal 'jsmith', p.login
   end
+
+  def test_use_safe_attributes_in_subclasses
+    b = Book.new
+    p = PublishedBook.new
+
+    b.safe_attributes = {'title' => 'My awesome Ruby Book', 'isbn' => '1221132343'}
+    p.safe_attributes = {'title' => 'The Pickaxe',          'isbn' => '1934356085'}
+
+    assert_equal 'My awesome Ruby Book', b.title
+    assert_nil b.isbn
+
+    assert_equal 'The Pickaxe', p.title
+    assert_equal '1934356085', p.isbn
+  end
 end