communications technology-supported international eSourcing of software products and services (IeS) can be effectively executed. The extant literature falls short of providing a systematic and detailed enough set of best practices to guide IeS. This paper presents best practices for IeS to facilitate further research, and to help managers and other stakeholders to understand, execute, and proac- tively improve and manage international eSourcing. The practices emphasize the need to establish and enact rigo- rous, mature, and quantitatively managed eSourcing life- cycles in order to transcend temporal, geographical, social, technical, and other boundaries in IeS. Keywords: Functional size measurement, Global soft- ware development, International eSourcing, Knowledge management, Outsourcing, Software process improve- ment, Software project estimation and benchmarking