Objective: Prenatal behavior, including nutrition, exercise, drug use and smoking, affects health of a pregnant woman and her fetus. Psychometric evaluation of the Prenatal Health Behavior Scale (PHBS) is important for developing research on measurement of such this behavior during pregnancy.Methods: The present descriptive study was conducted in 2018. The original version was in English, and was then translated into Persian after obtaining permission from tool designer and using Backward-Forward translation.The final Persian version included 240 pregnant mothers who were selected using random cluster sampling from hospitals affiliated to Shahid Beheshti University of Medical Sciences in Tehran. The factor analysis methods (exploratory and confirmatory), Pearson correlation, and Cronbach's alpha coefficient by SPSSV19 and LISRELV8.80 were used to analyze research findings.Results: Content validity and face validity were assessed by survey of 10 experts and 20 pregnant mothers.In general, the CVI was 94%.The confirmatory factor analysis indicated that all factor loadings were appropriate and significant in the initial model. Furthermore, coefficient alpha was 0.932 for prenatal health promoting behavior and 0.935 for Health-impairing behaviors. The values were acceptable and indicated the high validity of tool in the Iranian sample.Conclusion: The research findings indicated that the Prenatal Health Behavior Scale (PHBS) had acceptable psychometric properties among Iranian pregnant women and could be used as a valid tool for assessing prenatal health behavior in Iran.