Due to the prevailing positivistic view on science, qualitative research has only a modest place within the social sciences. There is, however, a growing awareness that a purely quantitative approach is not always satisfactory. This is for instance the case in the field of research into the quality of life. This article discusses a number of theoretical and methodological aspects of qualitative research. The following issues are dealt with: the (in-depth) interview as a research method, and the classification, analysis and interpretation of qualitative data. Subsequently views on the reliability and validity of qualitative research are discussed. After discriptions of a number of fields of application, the potential value of qualitative research is illustrated with reference to recent research.