Introduction: Physiological delivery program was implemented in mother-friendly hospitals of Iran after 2008. The aim of present study is to assess the effect of physiological delivery program in a mother-friendly hospital on duration of active phase and second stage of labor.Methods: This study was a clinical trial that was conducted at the Sinaand Ommobaninmotherfriendly hospitals in Ahvaz, Mashhad, Iran, in 2016. The intervention group of 77 women was offered the childbirth preparation classes during pregnancy and physiological delivery program during labor and the control group of 77 women received routine care.Results: The results showed that after controlling the confounding factors, the active phase and second stage of labor were significantly shorter in the intervention group (p<0.001). Conclusion: Complete implementation of physiological delivery program can reduce the duration of labor pain.Key words: Natural Childbirth; Prenatal Education; non-pharmacologic approaches; First stage of labor; Labor duration; Second stage of labo