Purpose <p>To evaluate the safety and efficacy of a fixed-dose combination (FDC) of tamsulosin prolonged release (PR) and tadalafil in moderate-severe benign prostatic hyperplasia (BPH) and erectile dysfunction (ED).</p> Methods <p>This was a single-arm, phase IV, prospective clinical trial in sexually active men aged 45–75 years with BPH [International Prostate Symptom Score (IPSS) score ≥ 8] and ED [International Index of Erectile Function-Erectile Function (IIEF-EF) score ≤ 25] who were taking tamsulosin 0.4&#xa0;mg PR and tadalafil 5&#xa0;mg. Eligible patients received FDC of tamsulosin+tadalafil (0.4 + 5&#xa0;mg) capsules for 12 weeks. The endpoints included treatment-emergent adverse events (TEAEs), total IPSS, IPSS storage and voiding sub-scores, maximum urinary flow rate (Q_max), post-void residual (PVR) volume, IIEF-EF (questions 1–5 and 15) score, and IPSS quality of life (QoL) index.</p> Results <p>A total of 172 were enrolled. Overall, 12 TEAEs were reported in 10 (5.81%) patients. None of the TEAEs were severe, serious, life-threatening, or required treatment interruption. A statistically significant improvement (<i>p</i> &lt; 0.0001) in total IPSS after 4, 8, and 12 weeks was observed. Similar improvements from baseline were also observed in IPSS storage and voiding sub-scores, IPSS QoL, Q_max, PVR volume, and IIEF-EF (questions 1–5 and 15) score (<i>p</i> &lt; 0.05 for each parameter). The proportion of men with normal erectile function significantly increased at week 12 (<i>p</i> = 0.0003).</p> Conclusion <p>The FDC of tamsulosin and tadalafil was associated with significant improvements in lower urinary tract symptoms and EF over 12 weeks and was well tolerated in Indian men with moderate-severe BPH and ED.</p> Trial registration <p>Prospectively registered at Clinical Trials Registry—India on 10th June 2022 [CTRI/2022/06/043152].</p>