A community sample of depressed and well mothers, recruited at 2 months postpartum and assessed through to 18 months, was followed up at 5 years. The quality of mother–child interactions was assessed, as was the children's behavioural and social adjustment, using maternal reports and observations of child behaviour during free play at school. Several aspects of child outcome were found to be associated with postnatal depression, even when taking account of current adverse circumstances (maternal depression and parental conflict). These included the child's behaviour with the mother, the presence of behavioural disturbance at home, and the content and social patterning of play at school. These associations with postnatal depression were independent of the child's gender. The child's relationship with the mother appeared to be mediated by the quality of infant attachment at 18 months. The mother's behaviour with her child was more affected by current difficulties, in particular by conflict with the child's father. Together these findings suggest that, while maternal behaviour varies with changing circumstances, exposure to maternal depression in the early postpartum months may have an enduring influence on child psychological adjustment.