This study aimed to evaluate social support and marital relationships in women with and without postpartum depression (PND), investigating the relationship between these constructs and the positive and negative impacts of each of them for the PND. A cross-sectional study was conducted with 67 women (32 with depression and 35 without depression) with children aged between 51 and 77 days. The results indicated that women with PND (assessed through the EPDS) had lower scores in perception of social support and identified their marital relationships as more conflicting. In the hierarchical model, demographic variables (baby’s age and maternal education) and marital relationship explained part of the variance of symptoms of PND. Social support did not prove to be a significant predictor in the model. Among the factors evaluated, the quality of the marital relationship was the most important to minimize the risk of developing PND, being an aspect subject to interventions by health professionals.