Handicaps in childhood often go by 2 or 3, more often than usually said. Multiple handicaps create difficult problems as to their diagnosis and care. On the basis of an epidemiological survey conducted in the Paris area, the authors underline the frequency of behavioral problems as supplementary handicap, and the role and importance of the mental deficiency in multiple handicaps in childhood, the most frequency associations according to the level of mental deficiency, the social factors significantly associated with the mental handicap, in terms of inequality of risks and inequality of access to health care and rehabilitation.