IT outsourcing has changed fundamentally since its start in the 1960’s. Since IT outsourcing services evolve and expand continuously, instruments to evaluate outsourcing success in user organizations need to be modified to meet these changes. Our study develops and conceptually validates a coherent and meaningful new instrument to measure the success of IT outsourcing. The instrument combines strategic, economic, technical and social success factors. The instrument is offered to researchers to be used in future studies. Correspondingly, our instrument provides practitioners with a useful tool to use in setting goals for IT outsourcing and for evaluating their achievement. .