A study was conducted in a Dutch hospital to evaluate the effects of the implementation of a Dutch form of Primary Nursing on nurses' well-being in the work situation. The variables used as indicators of well-being at work were job satisfaction, experienced job significance, health complaints and absenteeism. The study included three measuring periods: one pre-intervention (t1) and two post-intervention periods (t2, 8 months after t1, and t3, 14 months after t1). Primary Nursing was implemented in group 1 (consisting of two nursing units) after t1. At this time no changes were introduced into group 2 (three nursing units) but after t2. Primary Nursing was also implemented in group 2. The research variables were measured by means of questionnaires. The results of the study indicate that most of the expected effects of Primary Nursing did not occur. Some methodological and practical explanations for this outcome are given.