This article reports on an empirical study of industry PhD students in the Swedish Graduate School for Applied IT and Software Engineering. The students were questioned in semi-structured interviews about their experiences of sharing their postgraduate studies between industrial and academic environments. The results from the first analysis indicate that there are considerable differences between companies in terms of their traditions and their propensity to take part in joint knowledge development with universities. Three types of company environment were identified in this context: (a) research-intense, (b) engineering and (c) consultancy. The focus of this study is on how the type of activity, the difference in time perspective between companies and universities, the competence of other company employees and the character of the thesis project affect the doctoral student's situation, identity, support and participation in knowledge development. (Contains 7 tables and 2 figures.)