Health and fitness among children and adolescents is a subject currently receiving public attention. This article focuses on the fitness of German pupils (third and fourth grades) in five schools in Berlin with widely differing social catchment areas as well as children from differing social backgrounds. Besides an orthopaedic examination and measurements of height and weight, we tested the children's motor skills. In addition, a survey was carried out among pupils and their parents. For this purpose, questionnaires were developed which, besides furnishing demographic data, also provided information on attitudes towards the issue of sport and health as well as on sporting activities. In this contribution, we concentrate on the influence of parents and schools on the fitness and motor competencies of the children. The results of the test and the survey clearly showed correlations between the fitness level of the pupils and the education level of the parents. According to our results, fitness and physical skills are, at least to a certain extent, socially inherited. The fitness differences found in the different schools can be explained partly by the different social back ground of the children, but differences in facilities and provisions have also to be taken into consideration. Children who participated in a special programme and visited classes with an emphasis on physical education had a better fitness than pupils in "normal classes". However, most of the children in these special classes were from a middle-class background. (Contains 18 tables, 3 figures and 17 notes.)