Extension of condyloma acuminatum into the urinary bladder is rare. Only 4 cases of this disease undergoing malignant change have been reported. We report a 54-year-old man with extensive condyloma acuminatum of the urinary bladder and without a history of urethral and/or anogenital involvement. Though treated with transurethral resection and 5- fluorouracil (systemic and intravesical chemotherapy), frequent recurrence and evidence of local extension led to radical surgical treatment. Pathology revealed squamous cell carcinoma coexisting with condyloma acuminatum. (J Urol R.O.C., 8:157-161,1997)