Co-operation between research and industry and society, and the notion of innovation systems, are high on the agenda of national as well as international research politics. However, how to make co-operation between researchers and practitioners work, and what kind of research results could come out of such co-operation, is hardly discussed. The article uses evidence from three projects in the areas e-government and telecommunication to reflect on such co-operation. Scientific understanding and practices of design, development and use of ICT challenge and inform each other in these co-operative projects, which we have started to refer to as ‘situated innovation’. The article discusses the role of the researcher in such contexts, the character of the research results, and means to co-ordinate different rhythms and rationales in order to make research and practices of ICT development and use mutually enhancing.