diff --git a/lib/psych/visitors/yaml_tree.rb b/lib/psych/visitors/yaml_tree.rb
index ff0fcd20..29d66af0 100644
--- a/lib/psych/visitors/yaml_tree.rb
+++ b/lib/psych/visitors/yaml_tree.rb
@@ -512,7 +512,7 @@ def dump_ivars target
         ivars = find_ivars target
 
         ivars.each do |iv|
-          @emitter.scalar("#{iv.to_s.sub(/^@/, '')}", nil, nil, true, false, Nodes::Scalar::ANY)
+          @emitter.scalar("#{iv.to_s.sub(/^@/, ':')}", nil, nil, true, false, Nodes::Scalar::ANY)
           accept target.instance_variable_get(iv)
         end
       end
diff --git a/test/psych/test_object.rb b/test/psych/test_object.rb
index 5e3ce829..5d3114c8 100644
--- a/test/psych/test_object.rb
+++ b/test/psych/test_object.rb
@@ -19,6 +19,14 @@ def initialize parent
     end
   end
 
+  class WithNull
+    attr_accessor :null
+
+    def initialize
+      @null = true
+    end
+  end
+
   class TestObject < TestCase
     def test_dump_with_tag
       tag = Tagged.new
@@ -40,5 +48,12 @@ def test_cyclic_references
       assert_instance_of(Foo, loaded)
       assert_equal loaded, loaded.parent
     end
+
+    def test_null_named_ivar
+      original = WithNull.new
+      loaded = Psych.load(Psych.dump(original))
+
+      assert_equal(original.null, loaded.null)
+    end
   end
 end