The association between family structure and behavioural and emotional symptoms in prepubertal children was studied in an epidemiological survey conducted in Finland. Five thousand eight hundred thirteen children aged 8 and 9 years were screened using the Rutter Parent Questionnaire (RA2) for parents and the Rutter Teacher Questionnaire (RB2) for teachers. Information concerning family type, birth order and sibship size were obtained from the parents. The majority of the children (84%) in the sample lived with both their biological parents, 10% with a single parent, and around 5% with a biological parent and a stepparent. Around 1% of the children lived outside their original home. The prevalence of behavioural and emotional symptoms was lowest in children living with both their biological parents and highest among children living outside their original home according to both parents' and teachers' reports. Children living with a parent and a stepparent had problems more often at home, but less often at school than children living with a single parent. Living with a single father was associated with having more externalizing, school-related problems, while living with a stepfather was associated with having more internalizing, home related problems. Having younger siblings seemed to be associated with fewer problems at school, and being the youngest child with having less problems both at home and at school.