OBJECTIVES The investigation of the impact of early childhood risk factors on developmental outcome at the age of 11 years. METHODS The onset and course of developmental and behavioral disturbances were examined in a prospective longitudinal study of a sample of 362 children born with different risks. Organic (obstetric complications) and psychosocial risks (family adversity) were varied in a two-factorial design. Measures of motor, cognitive and social-emotional outcome were obtained from 341 children aged 11 years (168 boys, 173 girls, corresponding to 94.2% of the initial sample). Previous assessments had been conducted at the ages of 3 months, and again at the ages of 2, 4 1/2 and 8 years. RESULTS The negative impact of early risk factors persisted into late childhood. Rates of developmental and behavioral disturbances in high-risk children were up to three times higher than in non-risk children. Both organic and psychosocial risks contributed to adverse outcomes. While organic complications were related to disturbances in motor and cognitive development, the detrimental effects of psychosocial adversity pertained to social-emotional functioning. Late sequelae of pre- and perinatal complications were found especially in cognitive outcome and school performance. The cumulative effect of early risks was best explained by summing up the single risk effects. CONCLUSIONS Early risk factors have specific and long-term sequelae resulting in adverse school outcomes at later ages.