Aim: To assess depression in mothers of children born VP (<33 weeks) and its relationship to behaviour in the children at three years of age. Design: A regional cohort study. Participants: 728 children born VP in WA (1/1/90-30/6/92), 90 term control subjects .Measures: Mother- The Parenting Stress Index (PSI) - Depression Subscale. Infant- (1) Toddler Temperament Questionnaire (2) The Child Behaviour Checklist (CBCL) (3) PSI - Distractibility Subscale .Results: Data was available for 593/728 (81%) of VP and 90/90 (100%) of controls. There was no difference in depression (scores>90%) between VP(13%) and control (11%) mothers. Maternal depression in both VP and control mothers was associated with an increase in both problem behaviour (CBCL score>90%) [Adj RR 3.5 (2.5, 4.9)] and being more distractible (PSI score>90%) [Adj RR 2.9 (1.9, 4.5)]. Conclusions: Delivery of a very preterm infant is not associated with a higher prevalence of maternal depression later in the child's life. Mothers who are depressed report significantly more problem behaviour in their children. Follow-up studies that report behavioural outcomes must control for the maternal mood at the time of the assessment.