In the past two decades, type 2 diabetes mellitus has increased in children and adolescents, especially within certain ethnic groups. This increase has been parallel to the rising prevalence of obesity. Because of the overlap between some clinical characteristics, the differential diagnosis between type 1 and 2 diabetes is difficult. Of 300 diabetic patients in our diabetes section, only three (1 %) had type 2 diabetes. Two patients were obese adolescents with a positive family history of type 2 diabetes mellitus; the third patient was a prepubertal, overweight girl with no family history of this disorder. The diagnosis was incidental in two patients and one patient presented with ketoacidosis. The differences between the three patients reveal the great clinical variability of this disorder and suggest that various underlying factors are involved in the pathophysiology of type 2 diabetes.