Rats of the atherosclerosis-prone JCR:LA-corpulent strain were subjected to long-term low (0.5% wt/vol) or high (4% wt/vol) consumption of ethanol from 1 to 12 months of age. The corpulent rats are hyperphaglc, obese, and Insulin-resistant; exhibit a marked very low density lipoproteln hyperlipldemla; and develop both vascular and myocardlal lesions while eating a normal rat chow. The total lipld profile of the rat sera showed only limited changes with ethanol consumption. There were also no significant effects on high density lipoproteln llplds. Ethanol consumption was associated with elevated fasting glucose concentrations in both lean and corpulent rats and a strong decrease In fasting Insulin levels and pancreatic B-cell volume density In the hyperlnsullnemlc corpulent rats. The relative frequency of myocardlal nodules of chronic Inflammatory cells was Increased In the ethanolconsuming rats, both lean and corpulent. In contrast, old organized lesions (scars) were absent in the ethanol-consumlng corpulent rats. Thus, ethanol consumption had no major effect on serum llplds or lipoprotelns in the corpulent rat but was associated with a reduction In insulin resistance and Islet cell hyperplasla, with an associated decreased Incidence of myocardlal lesions. (Arteriosclerosis 9:122-128, January/February 1989) E pidemiologic studies in man have established that a wide range of risk factors are associated with the development of atherosclerotic disease and its sequelae.