The objective of the study was to investigate the gender-specific prevalence of emotional and behavioural problems in children and adolescents in out-of-home childcare, compared with patients in child and adolescent psychiatric institutions. The total population of clients in residential childcare institutions in Oslo, Norway, was investigated by the use of standardized questionnaires (Achenbach's Child Behavior Checklist and Youth Self Report) and compared to all same-aged patients residing in child and adolescent psychiatric institutions in the same area at the same time. Boys in residential childcare had emotional and behavioural problem levels comparable to boys in child and adolescent psychiatric institutions, as measured by the questionnaires. Girls in residential childcare did not reach problem levels as high as those found in girls in psychiatric institutions, but problem levels were still well above those found in the general population. It was concluded that institutionalized childcare clients had a high prevalence of behavioural and emotional problems, as measured by Achenbach's Child Behavior Checklist and Youth Self Report.