A 37-year old female was admitted with a complaint of gross hematuria. Intravenous pyelography and retrograde pyelography showed right non-functioning kidney with a radiolucent stone in the ureter. Computerized tomographic scan revealed right hydronephrosis and ureteral stone. Ureterolithotomy was performed. Infrared spectrometric analysis of the stone revealed a 2,8-dihydroxyadenine calculus. The adenine phosphoribosyltransferase activity in red blood cells was partially deficient. After the operation the patient has been given 100 mg/day of allopurinol and is on a low purine diet. There have been no signs of recurrence.