Objectives: To examine the influence of maternal pre-pregnancy body weight on fetomaternal outcomes in twin pregnancies. Study design: Retrospective study. Setting: Department of Obstetrics and Gynecology, Buergerhospital Frankfurt Population: 2,449 women delivering twins between 2005 and 2020 at the Buergerhospital Frankfurt. Methods: The mothers were categorized according to their pre-gravid body mass index into underweight, normal weight, overweight, obese, and obesity classes I – III. Main outcome measures: Gestational diabetes mellitus (GDM), preeclampsia/HELLP syndrome, intrauterine death (IUD), cesarean section or vaginal delivery, wound healing disorders, postpartum hemorrhage (PPH), uterine atony, preterm birth, birth weight discordance, admission to the neonatal intensive care unit (NICU), pH of the umbilical artery, and a 5’-APGAR score <7. Results: Obese mothers had a significantly higher risk for GDM (OR = 0.36; 95% CI 0.19 – 0.7 compared to underweight; OR = 0.32; 95% CI 0.23 – 0.43 compared to normal weight; OR = 0.47; 95% CI 0.33 – 0.69 compared to overweight), and wound healing disorders (OR = 0.19; 95% CI 0.09 – 0.4 compared to normal weight). Neonates of obese mothers showed significant results for umbilical artery pH of 7.01 – 7.1 (OR = 0.45; 95% CI 0.24 – 0.86 compared to overweight). Neonates of obesity class III mothers had a significantly higher risk for NICU admission (OR = 0.38; 95% CI 0.17 – 0.83 compared to obesity class I). No significant results for the remaining main outcome measures. Conclusions: Obesity, and overweight represent risk factors for adverse fetomaternal outcome in twin pregnancies.