Abstract-Zucker rats are a useful model in which to define the mechanisms that link obesity to diabetes and associated cardiovascular disease. The present study tests the hypothesis that diabetic obese (compared with nondiabetic lean) Zucker rats are hypertensive and display a further increase in arterial pressure when fed a high salt diet. Male, nondiabetic lean and diabetic obese Zucker rats were chronically instrumented with telemetry probes and fed a basal salt diet for 3 weeks followed by exposure to a high salt diet for 11 days. On the basal diet, obese (vs lean) rats had significantly higher arterial pressures (Ϸ13 mm Hg), and the high salt diet significantly elevated mean arterial pressure (MAP) in obese (but not lean) Zucker rats (Ϸ12 mm Hg). Blockade of the sympathetic nervous system with hexamethonium caused a significantly larger decrease in MAP in obese (vs lean) Zucker rats fed the basal diet (51 vs 33 mm Hg), but the high salt diet did not increase the hexamethonium-induced reduction in arterial pressure in obese rats. Acute blockade of angiotensin receptors with losartan resulted in similar decreases in MAP in both groups on either diet. Acetylcholine-induced vasodilatory capacity of the carotid artery was significantly less in the obese (vs lean) Zucker rats. Together these data indicate that increased sympathetic nervous system activity and decreased vascular reactivity may contribute to elevated arterial pressure in type 2 diabetic, obese Zucker rats, but the sympathetic nervous system does not appear to contribute to the dietary salt-sensitive hypertension in this model. which results in numerous pathological changes, including nephropathy, retinopathy, neuropathy, and cardiovascular disease. Of these factors, cardiovascular disease is the single largest cause of death in diabetes mellitus, accounting for an estimated 80% of deaths in diabetic individuals. 2 The risk of cardiovascular disease in diabetic individuals is increased by concomitant hypertension, which occurs in an estimated 70% of type 2 diabetic patients. 3 Results from the Framingham 4 and MRFIT 5 trials indicate that the coexistence of the 2 diseases triples the risk of cardiovascular disease. Moreover, the presence of hypertension probably accelerates diabetic nephropathy, which in turn exacerbates the hypertension, creating a vicious feedforward cycle that contributes to the extremely high occurrence of end-stage kidney failure in type 2 diabetic patients. 6