The relationship between impaired glucose tolerance (IGT) and blood lipid levels was examined in 65 IGT individuals and in two control groups: control group I, composed of age-, sex-, and body weight-matched controls, and control group II, including normal subjects matched for sex and age but with normal body mass index. IGT individuals were found to have significantly higher total triglyceride (Tg) values compared with normal weight controls (P less than 0.001), while no difference was found between IGT and control group I. Total cholesterol levels were similar in IGT and each of the control groups. No significant correlation was found between serum lipoproteins and blood glucose levels either fasting or after load.