Objectives : The aim of the study was to investigate factor structure of the Persian version of the Postpartum Stress Scale (PSS). Method: From accessible population and using a purposive sampling method, the current correlational study screened 142 people from all postpartum women at Zeinabiye State Maternity Hospital and gynecology and obstetrical departments in some non-state run hospitals (including Ordibehesht, Farahmandfar, Shafa, and Pars) in Shiraz during 1389 (2010-2011). Having no history of mental and physical disorders was considered as sample inclusion criteria. Data collection was based on Postpartum Stress Scale (PSS), Rosenberg Self-Esteem Scale (RSES), Multidimensional Scale of Perceived Social Support (MSPSS), and Beck Depression Inventory-II (BDI-II). Data analysis was performed using Pearson correlation coefficients and exploratory factor analysis (EFA). Results: Factor structure analysis by Varimax rotation method revealed two factors including “concerns about maternal role attainment and negative body changes”, and “concerns about lack of social support” accounted for 48.98% of the scale variance. Internal consistency for the whole scale and the extracted two factors depicted the high reliability of the scale. Divergent validity coefficients were confirmed using MSPSS and RSES and convergent validity coefficients using BDI. Conclusion: The results supported the validity and reliability of the PSS with regard to testing and conceptualizing postpartum stress of Iranian citizen women.