Depression following childbirth is associated with poor child growth in developing countries. We describe the association between psychological morbidity during pregnancy and low birth weight (<2.5 kg). A cohort of 270 mothers was recruited from a district hospital in Goa, India; all mothers were interviewed with a screening questionnaire for psychological morbidity. Babies of 250 mothers were reviewed at birth to measure their weight. Excluding 5 premature babies, we found that maternal psychological morbidity was independently associated with low birth weight (odds ratio 1.44, 95% CI 1.0-2.07). We conclude that maternal psychological morbidity has an adverse impact on foetal growth.