DEFINITION: Obese children have more than 20% overweight in relation to height. DIAGNOSTIC PROCEDURES: Estimation of serum concentrations of triglycerides, total-, HDL- and LDL-cholesterol, and of blood pressure; oral glucose tolerance testing in patients with more than 40% overweight. INDICATION FOR THERAPY: More than 20% overweight in relation to height. EVALUATION OF THERAPEUTIC RESULTS: Main goal: less than 20% overweight; if not possible, stabilisation of overweight between 20 and 30%; if not possible in cases of severe obesity (more than 60% overweight): Either reduction of overweight more than 40% (in patients with 80% overweight or more) or reduction of overweight more than 20 and less than 40% (in patients with 60-70% overweight) and stabilisation of overweight within these ranges respectively. Therapeutic results should be reported in relation to the end of therapy as short term results: at most 2 years, as medium term results: at least 3 years, and as long term results: after growth stop.