The execution process is critical to the success of a software outsourcing service. It defines the major roles and activities involved in delivering the outsourced software. This paper presents a process-oriented software outsourcing decision approach, which helps a client selecting appropriate vendors and defining the execution process that both the client and the vendors should comply with during the software outsourcing execution phase. First, decision impact factors are defined, which take into consideration characteristics of the project, of the client and of the vendors. For any given project, the value of each decision impact factor is acquired by sending a questionnaire to the stakeholders on both client and vendors sides. Then, the process decision based on factor values is conducted using genetic algorithm so that an optimized solution for vendor selection and process definition are generated. Simulation of the decision activity is conducted and it preliminarily verifies the feasibility of the approach. © 2010 IEEE.