The prevalence of obesity is increasing worldwide, and the rising number of obese children and adolescents is of particular concern. In humans, smoking is a predisposing factor for abdominal obesity, glucose intolerance and insulin resistance. Maternal smoking is associated with preterm birth and low birth weight. On the other hand, the incidence of obesity is higher in children and adults born of smoking mothers. Disorders in eating behaviour, reduced physical activity, and increased risk of hypertension and nicotine addiction have been observed in the offspring of smoking mothers. Evidence from animal and human studies suggests that intrauterine smoke exposure may alter peripheral and central mediators involved in the regulation of appetite and energy metabolism. Smoking cessation during pregnancy is desirable to improve health outcomes in offspring.