OBJECTIVES\nWe examined how maternal overweight impacts full breastfeeding (BF), total duration of BF and the age of introduction of complementary foods (CFs) and whether these have effect on children's growth from 0 to 2 years.\nSUBJECTS/METHODS\nFrom 1797 families participating in the STEPS Study, 848 children had data on BF and anthropometric data at 13 months and 2 years of age and were included in this study. Data on BF and CFs were collected using a self-administered follow-up diary. Information regarding maternal weight, height, pregnancy and delivery were received from maternity clinics and the National Longitudinal Census Files. The children's weight and length/height were recorded during the study visits at 13 months and 2 years.\nRESULTS\nOverweight women breastfed fully (2.2 vs 2.8 months, P<0.0001) and totally (7.4 vs 9.0 months, P<0.0001) for a shorter time and introduced CFs earlier (4.1 vs 4.3 months, P=0.02) than normal weight women. Children of overweight women were heavier and had a higher body mass index at 2 years than children of normal weight women. At 2 years of age 30% of boys and 17% of girls were overweight or obese. However, children's obesity risk was not increased by maternal overweight (odds ratio (OR) 1.04, P=0.12). Longer duration of full BF (OR 0.86, P=0.04) and partial BF (OR 0.91, P=0.02) and delayed introduction of CFs (OR 0.69, P=0.03) were protective against obesity.\nCONCLUSIONS\nOur study suggests that women who were overweight or obese before pregnancy breastfed for a shorter time and introduced CFs earlier than normal weight women, which may further impact children's growth.