High levels of triglycerides and free fatty acids have been implicated in the pathogenesis of type 2 diabetes mellitus (DM). Congenital generalized lipodystrophy (CGL) is an autosomal recessive syndrome characterized by intense whole body reduction of subcutaneous fat. Its clinical manifestations appear during the first years of life. However, DM is usually a late event. We report a patient with CGL, diagnosed at 4 months of age, who has severe hypertriglyceridemia (serum triglyceride 12.34 mmol/l and cholesterol 3.90 mmol/l), muscular hypertrophy, hepatomegaly and DM (fasting glycemia 25.9 mmol/l). Hepatic biopsy revealed steatosis and fibrosis. A modified normolipidic (composed of medium chain triglycerides) normocaloric normoproteic milky diet and insulin therapy were instituted. After 1 month treatment a reduction of serum glucose and triglyceride levels (4.13 mmol/I and 7.7 mmol/l, respectively) was noted, with later normalization, which led to the discontinuation of insulin therapy. The patient has been maintaining good control with diet alone, presenting normal serum lipid levels (triglycerides 1.07 mmol/l, total cholesterol 2.71 mmol/l) and the following glycemic profile at OGTT: 0' 4.4 mmol/l; 30' 7.0 mmol/l; 60' 3.8 mmol/l; 90' 5.3 mmol/l, and 120' 5.2 mmol/l. The disappearance of hepatic steatosis was evidenced by a biopsy obtained 1 year after the beginning of treatment. In conolusion, this report suggests that the DM occurring in CGL can be precipitated by high triglyceride levels.