This overview-methodological article is concerned with case studies designed for re¬search purposes, and leaves aside case studies that are used in teaching. The article is divided into three parts. In the first part the basic concepts are defined and an account is given of terms used in literature written in English. In this study a case study is characterised as a research approach that can involve a range of particular research methods. It is an approach that is integrated, holistic, and so tries to understand the constitutive components of a case and set the case (or several cases) studied in the context of real life. Most of en it seeks answers to questions of the type "how" and "why". In the foreign literature we can trace the crystallisation of two basic methodological approaches to the way in which case studies are conceived: the first identified with the socially con-structivist movement in research and has the character of qualitative research, while the second derives more from post-positivism and has the character of mixed research. This overview-methodological study looks at case studies that employ the mixed strategy. The second part of the article characterises the main types of case study, their possibilities and limits. These include: descriptive, exploratory, explanatory, instrumental, intrinsic and evaluative case studies. The third and longest part of the article describes the individual stages of the creation of a case study: the conception of the plan of a case study; choice of subjects, phenomena and institutions to be studied; data collection; data analysis; interpretation of the results; the possibility of generalising from the results achieved; writing up and publishing the case study.