The prevalence of pediatric obesity is increasing and many patients are followed by specialized centers or private doctors. The aim of this study was to verify short- and medium term results of a therapeutic approach based on nutritional intervention in a large pediatric population: 1383 subjects (695 females, 688 males) aged 10.1 +/- 2.7 yr, followed in 11 pediatric departments in Italy. No difference was found between centers in age, height, weight, BMI and IBW. The drop-out rate after the first visit was 30.2% (58.1% IBW > 140%) in females and 34.2% (70.7% IBW > 140%) in males. After two years of follow-up only 9.7% of females and 6.4% of males remained on treatment. Of these patients only 7.3% of females and 6.4% of males had IBW < 120%. These data show that an approach based on nutritional intervention alone is not sufficient for long-term treatment of pediatric obesity. Only an approach started early and involving the family can produce permanent results.