The last systematic review on the health consequences of child and adolescent obesity found little evidence on consequences for adult health. The present study aimed to summarize evidence on the long-term impact of child and adolescent obesity for premature mortality and physical morbidity in adulthood. Systematic review with evidence searched from January 2002 to June 2010. Studies were included if they contained a measure of overweight and/or obesity between birth and 18 years (exposure measure) and premature mortality and physical morbidity (outcome) in adulthood. Five eligible studies examined associations between overweight and/or obesity, and premature mortality: 4/5 found significantly increased risk of premature mortality with child and adolescent overweight or obesity. All 11 studies with cardiometabolic morbidity as outcomes reported that overweight and obesity were associated with significantly increased risk of later cardiometabolic morbidity (diabetes, hypertension, ischaemic heart disease, and stroke) in adult life, with hazard ratios ranging from 1.1-5.1. Nine studies examined associations of child or adolescent overweight and obesity with other adult morbidity: studies of cancer morbidity were inconsistent; child and adolescent overweight and obesity were associated with significantly increased risk of later disability pension, asthma, and polycystic ovary syndrome symptoms. A relatively large and fairly consistent body of evidence now demonstrates that overweight and obesity in childhood and adolescence have adverse consequences on premature mortality and physical morbidity in adulthood.