Plasma lipid and apolipoprotein levels of Type 1 and Type 2 young Kuwaiti diabetic women on insulin therapy were investigated to elucidate the relationship between coronary artery disease risk factors and lipid levels. Forty Type 1 and 52 Type 2 diabetic women and 45 and 62 corresponding control subjects (matched for age and body mass index) were investigated. In comparison with control subjects, both groups of diabetic patients showed marked increases in total-cholesterol, LDL-cholesterol, triglycerides, very low density triglycerides, apolipoprotein B, glucose, fructosamine, and glycosylated haemoglobin HbA1c (all p less than 0.001). However, apolipoprotein CIII was significantly elevated in Type 2 diabetic patients (p less than 0.001) but not in Type 1 patients. Concentrations of apolipoproteins CII and AII in both diabetic groups were not significantly different from those in control subjects. Levels of HDL-, HDL2- and HDL3-cholesterol and plasma apolipoprotein AI were markedly decreased in both the diabetic groups compared with their control groups (all p less than 0.001 except HDL3-cholesterol in Type 1 diabetic vs control, p less than 0.05). In Type 2 diabetic patients, HbA1c correlated positively with triglycerides (r = 0.70, p less than 0.001), cholesterol (r = 0.60, p less than 0.001), apolipoprotein B (r = 0.77, p less than 0.001), and apolipoprotein CIII (r = 0.55, p less than 0.001) and negatively with apolipoprotein AI (r = -0.49, p less than 0.001). In Type 1 diabetic patients HbA1c correlated positively only with apolipoprotein CIII (r = 0.50, p less than 0.001).