Background: Childbirth is among the most significant and pleasant events in a woman’s life. This event can be a traumatic event and a threat to the mother’s mental health. This study recognizes the relationship between Post-Traumatic Stress Disorder (PTSD) after childbirth and social support and marital satisfaction. Methods: This Cross-sectional analytical study was performed on a sample of 400 mothers who had delivered at Shohadaye-15-Khordad Hospital in Varamin (in two groups with & without PTSD). The research instruments include the Demographic, Midwifery, Neonatal Factors checklist, Enrich Marital Satisfaction, Weinfeld and Tigman Social Support, and the PTSD Symptoms Scale. We used SPSS to analyze the descriptive and Pearson correlation and logistic regression data. A P<0.05 was considered significant. Results: The prevalence of PTDS in this study was equal to 16.8%. There was no significant correlation between the mean of the total score of PTSD in all dimensions with social support (P>0.05). Marital satisfaction significantly affected the probability of PTSD after childbirth (P=0.001). There was a significant correlation between PTSD total score and dimension of avoidance symptoms and infant gender (P=0.038). There was also a significant correlation between gestational age and avoidance symptoms (P=0.001) and type of nutrition feeding and motivational symptoms (P=0.041) of PTSD dimensions. Conclusion: According to the relationship between marital satisfaction and PTSD, it is recommended to design suitable interventions to improve the marital status and promptly diagnose the susceptible mothers to prevent the spread of this complication.