Obesity, which has become an epidemic, is associated with considerable mortality and morbidity. Thus, special attention should be given to newborns with obese mothers. Knowledge of risk factors at birth for the development of childhood obesity could help to identify children who are in need of early obesity prevention efforts. This would help in development of strategies, which would help prevent obesity in preschoolers and young adults. This chapter covers the molecular mechanism behind obesity; the relationship of obesity with insulin resistance and metabolic syndrome and the role of adipokines in the pathophysiology of obesity. The chapter also discusses the effect of obesity on mother; effect of maternal obesity on fetal outcome and therapeutic interventions for controlling obesity.