For conducting questionnaire studies there exist generally recommended methods that were also respected during the project funded by the Grant Agency MoH CR - "Subjective approach of inhabitants of Ostrava to their health in association with their life-style, socio-economic status and education". The preparatory phase included the collection of literature and information on the investigated theme. The questionnaire had got five parts - A. General questions, B. Employment, C. Way of life, D. Health state and E. Personality. The validity of questionnaire was tested in the pre-research. In the main questionnaire study 3,000 questionnaires were sent. The total response rate was 21.1% (634 completed questionnaires). In the sample there were no differences in percentage rate by sex and age, but there are differences in the educational structure. After realizing the main questionnaire study, the repeatability study was carried out to find out the reliability of the answers. The response rate was 60.3% (181 questionnaires). The Kappa index and the total percentage of agreement were used for the evaluation of the repeatability study. The agreement was almost perfect and good in the total of 62.3 % of the questions. The quality of data was ensured by double data entry and by choosing the appropriate software. The selection of data for the complex analysis was based on the results of the repeatability study. On the basis of individual information from the questionnaire, new groups of individuals were generated. These groups of individuals were analysed further in relation to health and life-style by socio-economic factors in the models.