In order to analyse the role of long-term metabolic control on serum lipids of diabetic children, the authors studied 61 diabetics for a period of time of 18 months. The age of the patients ranged from 7.2 to 19.5 years; the patients were divided into two groups according to the presence of albumin excretion rate more than 15 micrograms/min: group A 46 children with albumin excretion rate less than 15 micrograms/min; group B 15 children with albumin excretion rate more than 15 micrograms/min. During the study, all the patients improved the quality of metabolic control but only in the diabetics of group A serum cholesterol and triglycerides levels fell significantly. The patients of group B did not modify their serum lipids concentrations in spite of the improvement of metabolic control. This study suggests that in the diabetic children with microalbuminuria it is difficult to normalize the lipid abnormalities by means of optimized insulin conventional therapy.