Two treatment strategies were compared to determine their effects on weight loss, body composition and risk factors for cardiovascular disease (CVD) in 32 obese children (relative weight>120%) aged 6-15 years. Modes of therapy included individual (Group I) or group treatment (Group II). The children were treated for 1 year and observed during the second year. Relative body weight decreased by 16.6% in Group I (p<0.001) and by 15.8% (p<0.01) in Group II during the first year; in both groups the lower relative body weight was maintained during the year of observation. No changes were observed in linear growth or lean body mass. Weight reduction was accompanied by increased high-density lipoprotein cholesterol (HDL-C) levels, increased ratio of HDL-C to total cholesterol, and reduced triglyceride concentrations in both groups. Fasting plasma insulin concentrations decreased significantly in Group I. In conclusion, intensive treatment produced significant weight loss, improved serum lipid profile and reduced hyperinsulinemia. These changes, if sustained, may reduce the risk of CVD later in life.