BACKGROUND The children of mentally ill parents have a higher risk of developing mental illnesses themselves over the course of their lives. This known risk must be taken into account in the practical provision of health care. METHODS Selective literature review. RESULTS The increased psychiatric risk for children of mentally ill parents is due partly to genetic influences and partly to an impairment of the parent-child interaction because of the parent's illness. Furthermore, adverse factors are more frequent in these families, as well as a higher risk for child abuse. Genetic and psychosocial factors interact with one another. For example, genetic factors moderate environmental effects; that is, the effect of adverse environmental factors depends on the genetic substrate. CONCLUSIONS Preventive measures for children of mentally ill parents urgently need improvement. In this article, positively evaluated programs of preventive measures are discussed. Essential prerequisites for success include appropriate, specialized treatment of the parental illness, psychoeducative measures, and special support (e.g. self-help groups) as indicated by the family's particular needs.