The relationship between extremely low birthweight (ELBW) and psychiatric disorder was investigated in a cohort of children of 500 to 1000g birthweight, born between 1980 and 1982. At five years of age data were collected for 82 of 90 survivors on psychiatric symptoms, parent-reported developmental delay and various aspects of psychosocial disadvantage. Compared with controls, ELBW children did not come from more disadvantaged environments, but were much more likely to experience developmental delay and problems with motor co-ordination. 16 per cent had an attention deficit disorder with hyperactivity (ADDH), compared with 6.9 per cent of controls. Rates of conduct disorder and emotional disorder were not raised, indicating that ELBW is a specific risk factor for ADDH. Controlling for the effect of neurodevelopmental problems rendered the association between ELBW and ADDH non-significant.