It was found that emotional disorders, conduct disorders and specific reading retardation were all twice as common in ten-year-old children attending schools in an inner London borough as in children of the same age on the Isle of Wight. The correlates of these disorders in the two areas were investigated in order to explore possible reasons for these differences in prevalence. It was possible to identify four sets of variables (family discord, parental deviance, social disadvantage and certain school characteristics) which were associated with child disorder and deviance within both the two areas. As in almost all cases these same adverse factors were more commonly found in London, it may be concluded that the high rates of psychiatric disorder and specific reading retardation in London ten-years-olds are due in part to the fact that a relatively high proportion of London families experience marital discord and disruption, that many of the parents show mental disorder and antisocial behaviour, that families often live in poor social circumstances, and that the schools are more often characterized by a high rate of turnover in staff and pupils. The evidence suggested that these problems stemmed from living in an inner London borough, but further research is required to identify what it is about life in a metropolitan area that predisposes to the development of disorder and deviance.