The studies were performed on 825 school-children 16-17 years old (512 girls and 313 boys) from first and second classes of secondary schools in some district towns in our country. 406 school-children attended public and 419 non-public schools. In the study was used a questionnaire worked out in the Institute for Children and Youth in Berlin. The analysis of the data collected by our co-workers of the District Sanitary-Epidemiological Stations enable the following conclusions: In both groups of pupils from the public and non-public secondary schools similar abnormalities in their everyday life detrimental for health were found. Improper dietary habits, sleep deficits, short time for physical activity belonged to the most important and most frequent lifestyle abnormalities. 18% of the respondents went to school without eating breakfast at home, 19% took their breakfast not every day and 3% of the examined pupils don't eat breakfast at all. During the working-days 14% of pupils were eating no warm meal. This was the cause more frequent in pupils from non-public schools (19%) than from public schools (4%). 18% of the respondents were eating not always dinner on working days. 82% of pupils were going to bed too late: 49% after 10 o'clock p.m. and 34% after 11 o'clock p.m. Greater irregularities were found among boys (92%) than among girls (76%). 13% of pupils from the public and non-public schools spent only 30 minutes, the way to school included, in the fresh air and 54% pupils in the public schools and 43% in non-public schools--about 1 hour.