Mild hyperuricemia in patients with essential hypertension reflects early renal vascular involvement. This report describes a retrospective analysis of 28 patients with unilateral renal arterial disease and hypertension who underwent surgical treatment. Following surgical repair of the arterial lesion: systolic pressure decreased from 188 ± 25 to 146 ± 21 mm Hg (p<0.001); diastolic pressure decreased from 108 ± 4 to 87 ± 6 mm Hg (p<0.001), and serum uric acid and creatinine concentrations decreased from 7.0 ± 1.1 to 6.1 ± 1.4 mg/dL and from 1.3 ± 0.3 to 1.0 ± 0.3 (p<0.02 andp<0.03, respectively). The reduced serum potassium levels, reflecting hyperaldosteronism, increased after surgical treatment (p<0.003). The 28 patients were classified in three groups according to previous therapy: group I (14 patients) had been treated with a centrally active adrenergic agonist or a beta adrenergic receptor blocking agent; group II (7 patients) had been treated with a diuretic, and group III (7 patients) had never received antihypertensive therapy. Serum uric acid concentrations were similar in each of the three groups and decreased significantly in each group after correction of the renal artery stenosis. These data strengthen our previous observations and further suggest that serum uric acid concentration may be useful as an index of renal vascular involvement in hypertension.