We encountered a case of familial juvenile gouty nephropathy (FJGN) with an autosomal dominant transmission pattern. Hyperuricemia in the propositus was caused by renal underexcretion of urate although his erythrocyte purine enzyme was normal. A renal biopsy specimen from the propositus showed interstitial fibrosis with tubular atrophy. On pyrazinamide and probenecid tests, the tubular secretion of urate selectively decreased without changes in either presecretory or postsecretory reabsorption of urate when his renal function was normal. Probenecid increased the urinary urate excretion and Cur/Ccr. The serum urate concentration was poorly controlled by allopurinol. When his renal function deteriorated, the uricosuric effects of both probenecid and benzbromarone were attenuated. However, the combined administration of probenecid with allopurinol decreased the serum urate concentration. These data suggest that the tubular secretion of urate is selectively impaired in FJGN and at the stage of renal failure, the combination of an uricosuric agent with allopurinol might be effective in treating hyperuricemia in FJGN.