We investigated the effect of deoxycorticosterone acetate (DOCA)-induced hypertension on plasma lipid and cholesterol levels and the development of vascular atherosclerotic changes in male Wistar rats injected with streptozotocin (STZ) or saline (CON). Rats given STZ alone demonstrated a mild hyperlipidemia and hypercholesterolemia without any change in blood pressure. One week of DOCA administration was without effect on blood pressure in CON and STZ groups, but at 3 and 6 wk caused a significant and similar elevation in both groups. This DOCA-induced elevation in blood pressure appeared to be associated with the increase in plasma lipid and cholesterol levels seen in both CON and STZ groups at 3 and 6 wk, although the elevation in lipid and cholesterol levels was significantly more pronounced in the STZ rats. Both CON and STZ groups injected with DOCA developed significant pathological changes in all vessels under investigation. However, the degree of atherosclerosis appeared, from a semiquantitative analysis, to be worse in the thoracic aortas and renal arteries of the STZ group. Neither normotensive group developed any atherosclerosis. It is concluded that hypertension is associated with atherosclerosis in normal rats and rats with short-term STZ-induced diabetes mellitus, although the higher plasma lipid and cholesterol levels of the latter group may potentiate the degree of vascular damage.