Objective: We aimed to compare pregnancy outcomes in association with placental pathology in pregnancies complicated by macrosomia in diabetic vs. non-diabetic women. Study design: Pregnancies complicated by macrosomia (>4000gr) were included. Pregnancy and delivery characteristics, neonatal outcomes and placental histopathology reports were compared between macrosomia in diabetic [pre-gestational or Gestational Diabetes Mellitus (GDM)] women (diabeticmacrosomia group) vs. non-diabetic women (non-diabetic macrosomia group). Adverse neonatal outcome was defined as >= 1 neonatal complications. Multivariate analysis was used to identify independent associations with adverse neonatal outcome. Results: The diabetic macrosomia group (n = 160) was characterized by higher maternal age (p = 0.002), Body Mass Index (BMI) (p < 0.001), and smoking (p = 0.03), and lower gestational age at delivery (p = 0.001). The diabetic-macrosomia group had higher rates of scheduled Cesarean deliveries (CDs) (58.9 % vs23.7 %,p < 0.001) while the non-diabetic macrosomia group (n = 214) had higher rates of emergent CDs (76.3 % vs.40.7 %,p < 0.001), perineal tears (p = 0.027) and Post Partum Hemorrhage (PPH) (p = 0.006). Placentas from the non-diabetic macrosomia group were characterized by higher rates of maternal and fetal inflammatory response lesions (p < 0.001). Except for higher jaundice rate in the diabetic macrosomia group (p < 0.001), none of the other neonatal outcomes including shoulder dystocia differed between the groups. In multivariate analysis GA < 37 weeks (aOR = 1.4,95 %,CI-1.2-3.9), and emergent CDs (aOR = 1.7,95 %,CI-1.4-4.1) but not diabetes (aOR = 1.1,95 %,CI-0.7-3.9) were associated with adverse neonatal outcome. Conclusions: Despite major differences in maternal demographics, mode of delivery, maternal morbidity, and placental characteristics- adverse neonatal outcome did not differ between macrosomia in diabetic vs. non-diabetic women and was high in both groups. Clinicians should be aware of the high rate of adverse neonatal outcome in macrosomic fetuses, even in the absence of diabetes mellitus. (C) 2020 Elsevier B.V. All rights reserved.