A patient with severe idiopathic hyperuricemia and hypokalemic alkalosis was followed over a one-year period. A tubulointersitial nephritis consistent with hypokalemic nephropathy was found on biopsy. However, the possibility that the hyperuricemia contributed to the hypokalemia and renal lesion cannot be excluded. Inappropriate urinary loss of potassium could be prevented by administration of spironolactone or triameterene. Six months after initiation of allopurinol therapy with reduction of serum uric acid concentrations to normal concentrations, this potassium wasting was substantially decreased.