58-year-old male with bladder cancer complicated acute myocardial infarction (aMI) were treated by 5-FU 300 mg/day orally for approximately one and a half months as single drug chemotherapy preoperatively. CT studies showed PR in bladder lesion and an improvement of bilateral hydronephrosis also. Biochemical evaluations as Thymidylate synthase inhibition and FdUMP were made on biopsy and operative specimens of urinary bladder. Clinical trials with 5-FU oral administration in bladder cancer were not held widely. Although its effectiveness and safety has been accepted in several fields. It was useful for a conservative operation case as single drug chemotherapy.