Postprandial lipoproteins, serumcholesterol and serum triglycerides were measured in 76 patients with juvenile diabetes mellitus. The lipoprotein pattern was pathological in 37% [type II (Frederickson) 20%; type IV 17%]. Serum cholesterol was not significantly elevated when compared with normals, but was positively correlated with the duration of the disease. Serum triglycerides were significantly elevated compared with normals.