['Increased neonatal weight gain has been suggested as risk factor for later overweight. Offspring of diabetic mothers (ODM) have a long-term increased overweight risk. However, the role of early postnatal weight gain for later overweight has not been addressed so far in ODM. We investigated whether increased weight gain during the first 4 months is related to later overweight in ODM.', 'Determinants of childhood overweight and neonatal weight gain were analyzed in 152 ODM from the Kaulsdorf Cohort Study by MANOVA and regression analyses.', 'Independent of birth weight, weight gain during the first 4 months was positively related to childhood relative body weight (P=0.001). Each 100 g-increase in weight during this period increased overweight risk by 65% (95%CI: 10-247%). ODM with rapid early weight gain had a more than six-fold increased risk of later overweight (OR: 6.77; 95%CI: 1.36-33.6). Early neonatal intake of breast milk from metabolically healthy mothers protected from rapid early weight gain (P=0.03).'] Does rapid neonatal weight gain increase risk of childhood overweight in offspring of diabetic mothers?