Six patients with congenital generalized lipodystrophy are described. They had generalized paucity of fat tissue, acanthosis nigricans, prominent superficial veins and muscle hypertrophy. They were mentally retarded. Three had corneal opacities. They had normal external genitalia and none was tall for age. Their bone age was advanced and some had minor skeletal anomalies and nephromegaly. The muscle histology on light microscopy was normal. The majority had elevated serum aldolase and to a lesser degree serum lactic dehydrogenase and creatinine phosphokinase. Four of five examined had a myopathic electromyogram. They had normal or deranged liver function tests. The fatty liver infiltration in one seems to be progressive. Four had a normal and two an abnormal metyrapone test. They had an age-dependent abnormality of growth hormone, insulin and carbohydrate homeostasis.