The Municipal Health Service for Rotterdam area in the Netherlands has developed a health research strategy with special focus on qualitative methods. This article describes one of the first and most instructive cases in which this strategy has been applied: a local health study in "Feijenoord." The research in Feijenoord was carried out between 1989 and 1990 making it possible to look both at the short-term and long-term effects. Quantitative data were used to describe the neighborhood health situation. Qualitative data were used to expand on this description. The qualitative information was obtained from residents and workers in health care and welfare using focused interviews and nominal group interviews. The results and effects of the research presented were influential. The research started a train of activity that could not have been predicted, and of which the Municipal Health Service had little control at first. An important effect in the short-term was that, as bringer of unpleasant news, the Municipal Health Service was unfavorably regarded. In the long-term, the Municipal Health Service participated significantly in the activities set up within the health framework. After evaluating these effects it was possible to formulate the conditions for an effective use of qualitative methods in public health research.