The popularity of focus group interview has rapidly grown in the last two decades. After long-time period in which this technique had been practiced almost exclusively in marketing research it begins the period of its frequent application in a great number of academic fields (sociology, psychology, evaluation research, public opinion research, communication, medical care). Only with the intensification of investigations in which focus group interviewing has been applied it was enabled achieving of experience that can be methodologically generalized, with accompanying development of the technique. This text refers to the basic methodological principles of this technique's application. In the paper the methodological experiences are synthesized which are accumulated through an enormous number of foreign explorations, as well as in many-year research experience of the author.