Although the qualitative approach is not the core one in demography, demographers show an increasing interest in this type of research. An aim of this article is to outline the benefits of applying the qualitative methods in the population studies. The article starts from sketching the main characteristics of the qualitative methodology. The logic of the qualitative research process is presented and the possible procedures of sampling, data collection and data analyzing are described. Next, some examples of the recent qualitative research projects are given, which deal with the problems of population dynamics. We choose the ones that investigate the fertility and family dynamics, indicating what additional insights can be gained by adding the qualitative methods to statistical analyses. Our focus is on the two studies that explore the lowest-low and delayed fertility in the Polish context. We summarize the paper by delineating the main benefits of combining qualitative and quantitative methods in the field of population studies, strongly advocating such mixed approach for the future demographic research.