Plasma HDL, HDL2 and HDL3 were determined in 95 untreated and 87 treated patients with NIDDM and 86 cases with IGT using Eder's modified method.The result showed that HDL, HDL2 and HDL3 were all reduced in these three groups in comparison with control group, but the average concentrations of all 3 subfractions of HDL showed no significant difference among these three groups. It also indicated that HDL abnormality may appear quite early in cases with abnormal glucose tolerance, such as in patients with IGT.