Background: The presense of women in workplace is an unavoiding issue in modern world. The women work in different media. Occupational activities are suspected of having an adverse impact on outcomes of pregnancy. Premature delivery is a catastrophic event in course of pregnancy. The aim of the study was to define the incidence of premature delivery in occupationally involved pregnant women. Material and Methods: A total of 287 primigravida women in an urban society with singleton pregnancies at 22 to 24 weeks gestation were enrolled in a prospective study. They worked in industrial manufactures. The patients reported the number of hours worked per week and answered specific questions designed to determine the following 5 sources of occupational fatigue including:1- posture ,2- work with industrial machines 3- physical exertion 4-mental stress and 5- environmental stress. Results: The risk of preterm delivery increased with standing more than 3 hours during activities in work place (p.value=0/019). There was not a statistically significant relationship between premature delivery and other sources of occupational fatigue. There was not a statically significant relationship between premature rupture of fetal membranes and the sources of occupational fatigue. There was not a statistically significant relationship between premature delivery and increasing number of hours worked per week. Conclusion: The relationship between premature delivery and occupational fatigue may provide guidelines according to pregnant women and their employers can be advised.