Six children with partial lipodystrophy have been studied. Oral glucose tolerance was not grossly impaired but fasting serum insulin (19.4,±6.3μUml) was higher than normal, and hyperinsulinaemia after oral glucose (maximum 250μUml) was present in 3/6 children. Plasma growth hormone was normal; serum cortisol was low in 1/6 children. Fasting serum cholesterol, triglyceride, and plasma non-esterified fatty acids were normal. Fatty acid composition of adipose tissue triglyceride from non-dystrophic areas in 3/3 children showed an increased proportion of palmitoleic acid (8.8, 10.0, 11.0%) compared with normal (5.8 ± 1.5%). Plasma post-heparin lipolytic activity was normal in 3/4 children. Sweat production and sodium concentration did not differ between lipodystrophic and normal areas in 2/2 patients. Treatment with propranalol, in an attempt to inhibit sympathetic mediated lipolysis, had no beneficial effect in 2/2 children over a 4-6 month period. The results suggest that increased insulin resistance is present at an early stage of the disease, but do not provide evidence for sympathetic nervous system overactivity.