Two studies of the effects of components of the integrated Nursing Information System VISION, involving five Dutch hospitals, were concluded in 1996. This paper summarises these studies and their results. The studies assessed effects on workload, quality of co-ordination, job satisfaction, patient satisfaction and quality of information supply. In both studies a quasi-experimental approach was followed. The results show significant positive effects with respect to quality of co-ordination, nurses job satisfaction and patient satisfaction. Workload measurements revealed a shift in the nurses' activities, but no change in the amount of time spent on patient care. On the basis of the positive results, 4 of the 5 hospitals have decided to extend the use of the system.