It is only during the past few years that the sourcing of IT has become an important issue for most organisations. Downsizing, the move to flatten organisations and the search for added flexibility, are cited as major reasons for this interest. Additionally, for the UK public sector, government pressure and legislative requirements have been instrumental in making many organisations consider outsourcing. Transaction cost analysis provides an economic approach to selecting the most appropriate source. However, in itself it is not enough, since it fails to take account of the special features of knowledge-intensive goods and services. This form of analysis needs to be augmented with considerations of these special features and of the organisational and environmental factors surrounding the sourcing decision. This paper provides this augmentation within a comprehensive framework for IT sourcing decision making.