Shift work during reproductive age can be a risk factor for metabolic syndrome. The present study evaluated the association between shift work and metabolic syndrome during reproductive age. This multi-center cross-sectional correlational study was performed between September 2017 and May 2018. A total of 419 female shift and day workers were purposively recruited to the study from three central cities in Mazandaran, Iran. To diagnose metabolic syndrome based on the National Cholesterol Education Program Adult Treatment Panel III guidelines, the anthropometric measures, blood pressure, and levels of serum triglyceride, high-density lipoprotein and fasting blood sugar were taken. Data were analyzed using the independent-sample t, Chi-square and the Fisher's exact tests as well as the logistic regression analysis. Among the 419 participants, 28 were excluded during the study. The total prevalence of metabolic syndrome was 16.3%, and its prevalence among shift workers and day workers was 17.3 and 14.9%, respectively. The most prevalent components of metabolic syndrome were low serum level of high-density lipoprotein and abdominal obesity. Following adjustments for the effects of potential cofounders, the logistic regression analysis revealed that the odds of metabolic syndrome among shift workers was ~2 times greater than day workers (odds ratio, 1.83; 95% confidence interval, 0.088-3.79), although this association was statistically insignificant (P=0.10). The results of the current study suggest that shift work is associated with a greater risk of metabolic syndrome for women. The most important components of metabolic syndrome are low serum level of high-density lipoprotein and abdominal obesity, which are attributable to limited physical activity and high occupational stress. The risk of metabolic syndrome among female shift workers of reproductive age may be reduced through strategies, including awareness raising, dietary educations and provision of physical activity facilities in the workplace.