This study attempts to develop a general aetiological concept of essential hypertension by multidimensional investigation of its various risk factors in childhood and adolescence. The investigation is based on married couples and their children (609 parents and their 639 children, a total of 1248 persons), all of them chosen under special aspects. Familial and environmental characteristics of children and young people with hypertension are compared with those of normotensive volunteers of the same age. The multi-dimensionally interacting factors found to be associated with hypertension in children are: hypertension, diabetes and early infarction in relatives of the first or second degree as well as overweight at birth, obesity, nutritional patterns in the earliest and later stages of life, social environment and physical activity of the children and adolescents. The familial factors most likely lead to a predisposition to hypertension while environmental factors may subsequently contribute to its manifestation.