Background & Objective: Regional differences exist in the prevalence of birth defects. This study was undertaken to determine the prevalence and related factors with birth defects in Zanjan, Iran. Materials & Methods: This descriptive analytic study was performed in Zanjan province during 2015-2016. Data included 41265 child births, which were extracted from the Iranian Mother and Newborn (IMAN) web system report of the Zanjan province hospitals (country electronic childbirth register system). Data was analyzed using descriptive, uni-variate, and multi-variate logistic regression tests. Results: The prevalence of birth defects in Zanjan was 0.7%. Gestational age (odds ratio [OR]: 0.917, 95% CI: 0.869-0.967, P=0.002) and birth weight (OR=0.999, 95% CI: 0.999-1.000, P< 0.001) reduced the chance of birth defects, while consanguineous marriage of parents (OR: 1.745, CI 95%: 1.298-2.347, P<0.001), and mother's doctoral degree increased its prevalence (OR: 3.928, 95% CI: 1.058-14.584, P=0.041). Conclusion: It seems that premarital counseling, screening tests before and during pregnancy, and education, especially for being pregnant in appropriate age and conditions, could be the suitable approaches for reducing birth defects.