The occurrence of multimetabolic syndrome was studied in 114 (63 boys, 51 girls) obese children. From the blood sample taken after on overnight fast blood sugar, serum insulin, and lipid levels were determined. During oral glucose tolerance test blood sugar concentrations were followed. Body mass index, body fat (on the basis of skinfold measurements), lean body mass and waist/hip ratio were calculated and blood pressure was measured 6 times in all subjects. Multimetabolic syndrome was found in 16% of boys and 19.6% of girls. No significant sex difference in the frequency of multimetabolic syndrome was found. Patients with multimetabolic syndrome could not be characterized by high waist/hip ratio any other antropometric parameter. The duration of obesity was significantly higher in subjects with multimetabolic syndrome than in those not suffering from the syndrome. This finding supports the hypothesis that the development of the multimetabolic syndrome is a process. The authors emphasize the significance of this problem and the importance of early recognition and prevention.