Aim. The primary purpose of this study was to translate the Lowe's Childbirth Self-Efficacy Inventory to Persian and to examine the psychometric properties of its Iranian version. Background. Self-efficacy for childbirth has been found to be a factor in a woman's decision about her choice of delivery and an essential key in coping with labour pain. Creating a valid and reliable questionnaire is necessary to gain a better understanding of the emotional preparation of pregnant women. It is also essential for the development of educational interventions and improving the sense of self-efficacy during pregnancy. Design. Questionnaire translation. Methods. The standard 'forward-backward' procedure was applied to translate the questionnaire from English into Persian (Iranian language) and then was reviewed by a panel of experts. We used exploratory factor analysis to examine the construct validity of the instrument. To test the reliability, Cronbach's coefficient alpha was employed. A random sample of 176 pregnant women, attending public prenatal clinics in Tehran, was recruited for participation in the study. Results. The results indicated that each subscales of Childbirth Self-Efficacy Inventory is essentially a unidimensional scale. The results revealed that Iranian pregnant women were able to distinguish between self-efficacy expectancy and outcome expectancy, but they did not differentiate the active phase of labour from second stage. Religious or spiritual beliefs were found to have an important role in the Iranian version of the Childbirth Self-Efficacy Inventory. Conclusion. This preliminary study of the Iranian version of the Childbirth Self-Efficacy Inventory showed that it is an acceptable, reliable and valid measure of women's belief and their confidence in coping with labour pain. Relevance to clinical practice. A culturally sensitive, reliable and valid instrument is crucial to better understand the self-efficacy of childbirth as a basis for developing effective interventions to increase normal childbirth among Iranian pregnant women.