This study is intended to develop the Taiwanese version of the Edinburgh Postnatal Depression Scale (EPDS-T), to evaluate its validity, and to estimate the prevalence of postpartum depressive disorders (PPD) among Taiwanese women. A prospective cohort of 203 subjects who completed the EPDS-T, the Beck Depression Inventory (BDI-II), and postpartum questionnaire at 6 weeks after giving birth were assessed with the Mini-International Neuropsychiatric Interview (MINI) and DSM-IV to establish their psychiatric diagnoses. We tested the validity of EPDS-T against the clinical diagnoses and compared its applicability with BDI-II. We found that the Taiwanese version of EPDS-T had satisfactory sensitivity and better specificity than BDI-II, that the 12/13 cutoff point was the best for screening PPD, and that 10.3% of the study population suffered from depressive disorders at 6 weeks postpartum. Based on the findings of this study, we suggest that PPD prevalence among Taiwanese women is not lower than that among most Western populations and that the validated EPDS-T can be used for early detection and management of postpartum depression in Taiwan.