In this multicentre, double-blind study, patients with LUTS/BPH were randomised to 26 weeks with finasteride 5 mg once daily (n=204) or tamsulosin 0.4 mg once daily (n=199). Double-blind treatment was continued for another 26 weeks (total treatment duration: 1 y). The primary efficacy parameter was the difference in mean change in total Symptom Problem Index (SPI) from baseline to end point at week-26 in the intention-to-treat (ITT) and per protocol (PP) populations. Tamsulosin induced a greater improvement in total SPI (-5.2 points or -37%) compared to finasteride (-4.5 points or -31%) at week-26 (P=0.055 in ITT and P=0.032 in PP). Tamsulosin improved urinary symptoms (particularly the more bothersome storage symptoms) and flow more quickly than finasteride. The difference was statistically significant for the SPI from week-1 (reduction, respectively, -2.5 vs -1.8 points, P=0.043) to week-18 and for Qmax from week-1 (increase, respectively, 2.3 vs 0.7 ml/s, P=0.0007) to week-12. Both treatments were well tolerated with a comparable incidence of adverse events, including urinary retention.