Purpose We identify predictors of clinical response as well as response time in patients treated with finasteride for gross hematuria due to benign prostatic hyperplasia. Materials and Methods A retrospective chart review was preformed of 53 patients who had been given 5 mg. finasteride daily for the treatment of active bleeding or a recent history of recurrent bleeding. Urological evaluations were negative for tumor in all patients. A history of prostatectomy, anticoagulant status and prostate size was determined. The degree of hematuria was then graded before and after finasteride treatment according to our previously described system. Of the 53 patients who were actively bleeding at initial evaluation 16 were followed to determine time required for complete resolution of hematuria. Results Hematuria grade improved after finasteride in 50 (94%) patients. Overall 77% of patients (41 of 53) experienced no further bleeding while taking finasteride. Mean followup was 38 months (range 3 to 86). Of the patients 86% (12 of 14) taking coumadin, 77% (10 of 13) taking aspirin and 73% (19 of 26) on no anticoagulants had no further bleeding once on finasteride. Of the patients who had undergone prior transurethral prostatectomy 84% (26 of 31) experienced no further bleeding versus 68% (15 of 22) of those who had not undergone previous surgery. In the 16 patients who began finasteride while actively bleeding the average time to clear urine was 12 days (range 2 to 45). Prostatic volume correlated with the average time needed for resolution of hematuria, which was 2.7 days or longer for small (less than 40 gm.), 10.3 days or longer for large (40 to 100), 19 days or longer for extra large (100 to 150) and 45 days or longer for extra extra large (greater than 150) glands. Hematuria resolved an average of 5.5 days versus 18.6 days in those who had or had not undergone previous prostatectomy, respectively. Conclusions Our long-term followup demonstrates finasteride as a useful treatment for benign prostatic hyperplasia related gross hematuria, which is effective in patients who are on anticoagulants. In patients with larger prostatic volumes a longer time to response and higher incidence of recurrent but lower grade bleeding should be anticipated compared to those who have undergone prior prostatectomy or have a smaller prostate.