Background: Low birth weight (LBW) is considered as one of the important health indicators in evaluating prenatal care as well as determining scale of infants' health in the society. The study aimed to investigate maternal diseases during pregnancy and its impact on LBW in rural areas of Kurdistan province, Iran. Materials and Methods: This study was conducted in nested case-control study method in rural areas of Kurdistan province- Iran in 2015-2016. In this study, 182 infants less than 2,500gr as case and 364 infants weighing 2,500 g and more as control were entered the study. Information about case and control groups was extracted by investigating records of pregnant women care. Data was analyzed using software Stata-12 with point and interval estimation of odds ratio (OR) using conditional logistic regression. Results: The results of single-variable analysis of conditional logistic regression showed that there is a statistical relationship between blood pressure during pregnancy, iron deficiency anemia, mother's thyroid problems, oral and dental problems, and history of bleeding during pregnancy in case and control groups (P<0.05). The results of multivariate analysis in the presence of other factors affecting underweight during pregnancy showed that there was statistically significant relationship between iron deficiency anemia (OR=23.86, 95%CI, 9.31-61.11), blood pressure during pregnancy (OR=13.8, 95%CI, 13.8-60.65), history of bleeding during pregnancy (OR=9.21, 95%CI, 3.39-25.01), and low birth weight (P<0.05).Conclusion: The results of this study indicated significant relationship between the diseases of pregnancy (such as blood pressure during pregnancy, iron deficiency anemia, and history of bleeding during pregnancy) and Low birth weight in infants. The birth of a LBW infant can be to a large extent prevented by diagnosing and preventing these diseases and required trainings for pregnant women.