Plasma lipids and lipoprotein levels were measured in 100 patients who underwent coronary angiography for chest pains. The coronary arteries were normal in 33 patients (22 males and 11 females), moderately pathological (30--60% narrowing) in 4, and markedly pathological (greater than 60% narrowing) in 63 (53 males and 10 females). Plasma cholesterol and triglyceride levels and very low and low density lipoprotein cholesterol levels were higher by 20--40% in both males and females with pathological coronary arteries as compared to normals. The high density plasma lipoprotein cholesterol level was lower in females with pathological arteries than in normals, but did not differ between the male groups. 67% of the males with pathological arteries had hyperlipoproteinemia as compared to 26% of the normals, and hyperlipoproteinemia was as frequent among males emigrating to Isreal from Europe or America as among those born in Asia or Africa. Hyperlipoproteinemia types IIA, IIB and IV were encountered among the patients at similar rates.