OBJECTIVE to investigate the relationship between maternal physical health problems and depressive symptoms in the first year after childbirth. DESIGN prospective pregnancy cohort study. SETTING Melbourne, Victoria, Australia. POPULATION 1507 nulliparous women. METHODS women were recruited from six public hospitals between six and 24 weeks gestation. Written questionnaires were completed at recruitment and at three, six and 12 months post partum. OUTCOME MEASURES Edinburgh Postnatal Depression Scale (EPDS); standardised measures of urinary and faecal incontinence, a checklist of symptoms for other physical health problems. RESULTS overall, 16.1% of women reported depressive symptoms during the first 12 months post partum, with point prevalence at three, six and 12 months post partum of 6.9%, 8.8% and 7.8% respectively. The most commonly reported physical health problems in the first three months were tiredness (67%), back pain (47%), breast problems (37%), painful perineum (30%), and urinary incontinence (29%). Compared with women reporting 0-2 health problems in the first three months post partum, women reporting 5 or more health problems had a six-fold increase in likelihood of reporting concurrent depressive symptoms at three months post partum (Adjusted OR=6.69, 95% CI=3.0-15.0) and a three-fold increase in likelihood of reporting subsequent depressive symptoms at 6-12 months post partum (Adjusted OR=3.43, 95% CI 2.1-5.5). CONCLUSIONS poor physical health in the early postnatal period is associated with poorer mental health throughout the first 12 months post partum. Early intervention to promote maternal mental health should incorporate assessment and intervention to address common postnatal physical health problems.