This study assesses the prevalence and determinants of postpartum depression (PPD). 396 women delivering in Beirut and a rural area (Beka'a Valley) were interviewed 24 hours and 3-5 months after delivery. During the latter visit, they were screened using the Edinburgh postnatal depression scale. The overall prevalence of PPD was 21% but was significantly lower in Beirut than the Beka'a Valley (16% vs. 26%). Lack of social support and prenatal depression were significantly associated with PPD in both areas, whereas stressful life events, lifetime depression, vaginal delivery, little education, unemployment, and chronic health problems were significantly related to PPD in one of the areas. Prenatal depression and more than one chronic health problem increased significantly the risk of PPD. Caesarean section decreased the risk of PPD, particularly in Beirut but also in the Beka'a Valley. Caregivers should use pre- and postnatal assessments to identify and address women at risk of PPD.