Objective: Evaluate the effect of dutasteride in perioperative bleeding during Transurethral Resection of Prostate (TURP). Materials and Methods: Forty consecutive patients with criteria for TURP were included. Finasteride/dutasteride use, renal impairment, prostate < 30 cc, age < 50 were excluded. Patients were divided in 2 groups. Group 1: 24 consecutive patients treated with dutasteride 0.5 mg/day/30-days prior TURP. Group 2: 16 without treatment. Prostatic volume, difference in hemoglobin pre/post TURP, duration and amount of resected tissue were recorded. Surgeon was blinded. Statistical analysis: Multiple linear regression, Mann-Whitney and student t-tests were used. Results: In group 1, 33%(8) improved their lower urinary tract symptoms and skipped TURP. Mean Hemoglobin loss difference between groups was 0.11 gr/dl (CI 95% -0.55; 0.77, p=0.88). There was no statistical difference among variables. No positive or negative predictive values in the linear regression model. Conclusion: Dutasteride did not significantly impact the studied variables in these non randomized and small sample size settings. (C) 2010 AEU. Published by Elsevier Espana, S.L. All rights reserved.