diff --git a/python/GafferRenderManTest/RenderManShaderTest.py b/python/GafferRenderManTest/RenderManShaderTest.py
index fcff2a3dd14..c2bbe352f6c 100644
--- a/python/GafferRenderManTest/RenderManShaderTest.py
+++ b/python/GafferRenderManTest/RenderManShaderTest.py
@@ -1003,6 +1003,48 @@ def testCoshaderTypeAnnotations( self ) :
 		self.assertFalse( shaderNode["parameters"]["coshaderArrayParameterType2"]["in1"].acceptsInput( coshaderNode["out"] ) )
 		self.assertFalse( shaderNode["parameters"]["coshaderArrayParameterType2"]["in1"].acceptsInput( coshaderType1Node["out"] ) )
 		self.assertTrue( shaderNode["parameters"]["coshaderArrayParameterType2"]["in1"].acceptsInput( coshaderType2Node["out"] ) )
+	
+	def testSplitCoshaderPassThrough( self ) :
+	
+		#   C ----S      S is connected to C both directly
+		#   |     |      and as a pass-through of the disabled
+		#   D ----       node D.
+		#
+	
+		shader = self.compileShader( os.path.dirname( __file__ ) + "/shaders/coshaderArrayParameters.sl" )
+		S = GafferRenderMan.RenderManShader()
+		S.loadShader( shader )
+				
+		passThroughCoshader = self.compileShader( os.path.dirname( __file__ ) + "/shaders/coshaderWithPassThrough.sl" )
+		D = GafferRenderMan.RenderManShader()
+		D.loadShader( passThroughCoshader )
 		
+		coshader = self.compileShader( os.path.dirname( __file__ ) + "/shaders/coshader.sl" )
+		C = GafferRenderMan.RenderManShader()
+		C.loadShader( coshader )
+
+		S["parameters"]["fixedShaderArray"][0].setInput( C["out"] )
+		S["parameters"]["fixedShaderArray"][1].setInput( D["out"] )
+		D["parameters"]["aColorIWillTint"].setInput( C["out"] )
+		
+		h = S.stateHash()
+		s = S.state()
+		
+		self.assertEqual( len( s ), 3 )
+		self.assertEqual( s[2].parameters["fixedShaderArray"], IECore.StringVectorData( [ s[0].parameters["__handle"].value, s[1].parameters["__handle"].value, "", "" ] ) )
+		self.assertEqual( s[0].name, coshader )
+		self.assertEqual( s[1].parameters["aColorIWillTint"], s[0].parameters["__handle"] )
+		self.assertEqual( s[1].name, passThroughCoshader )
+		
+		D["enabled"].setValue( False )
+
+		self.assertNotEqual( S.stateHash(), h )
+		
+		s = S.state()
+		
+		self.assertEqual( len( s ), 2 )
+		self.assertEqual( s[1].parameters["fixedShaderArray"], IECore.StringVectorData( [ s[0].parameters["__handle"].value, s[0].parameters["__handle"].value, "", "" ] ) )
+		self.assertEqual( s[0].name, coshader )
+			
 if __name__ == "__main__":
 	unittest.main()
diff --git a/src/GafferScene/Shader.cpp b/src/GafferScene/Shader.cpp
index 7c35ebf0fb4..4e13e8e7bf8 100644
--- a/src/GafferScene/Shader.cpp
+++ b/src/GafferScene/Shader.cpp
@@ -284,9 +284,13 @@ const std::string &Shader::NetworkBuilder::shaderHandle( const Shader *shaderNod
 		return emptyString;
 	}
 	
-	s->setType( "shader" );
-	IECore::StringDataPtr handleData = new IECore::StringData( boost::lexical_cast<std::string>( shaderNode ) );
-	s->parameters()["__handle"] = handleData;
+	IECore::StringDataPtr handleData = s->parametersData()->member<IECore::StringData>( "__handle" );
+	if( !handleData )
+	{
+		s->setType( "shader" );
+		handleData = new IECore::StringData( boost::lexical_cast<std::string>( s ) );
+		s->parameters()["__handle"] = handleData;
+	}
 	return handleData->readable();
 }