Summary Introduction: While a growing body of evidence has investigated the relationship between maternal mental health and child development, evidence on children’s early life outcomes remains mixed. We analyze the empirical relationship between maternal depression and children’s development at age one using data from the São Paulo Western Region Cohort project. Method: Seven hundred and ninety-eight (798) mother-child dyads living in the Butantã-Jaguaré’ region of São Paulo were assessed through a home visit between January and March 2015. Maternal mental health was assessed using the Edinburgh Postnatal Depression Scale (EPDS). Mothers were classified as “possibly depressed” if their EPDS score was between 10 and 13 and as “likely depressed” if their EPDS score was > 13. The child outcomes analyzed were height, weight, and overall development as assessed by the Ages and Stages Questionnaire (ASQ). Height and weight were age-normalized using WHO growth standards. Stunting was defined as height-for-age z-score (HAZ) 2. Adjusted and unadjusted linear regression models were used to assess the associations between Edinburgh scores and child outcomes. Results: No association was found between maternal depression variables and children’s height, weight, stunting, and obesity. Positive associations were found between possible depression and ASQ (delta = 0.33; 95CI 0.11-0.54; p-value