Epidemiological data link erectile dysfunction (ED) and benign prostatic hyperplasia (BPH)-associated lower urinary tract symptoms (LUTS), two highly prevalent conditions in aging men, assuming common pathophysiological pathways. Tadalafil 5 mg once daily has been approved for the treatment of men with LUTS with or without comorbid ED. The aim of this review is to provide an overview of current knowledge on the epidemiological and pathophysiological links between ED and LUTS and to focus on tadalafil as a new treatment option in men with BPH-associated LUTS. A Medline search was completed using the Medical Subject Headings (MESH® keywords) ‘prostatic hyperplasia’ and ‘phosphodiesterase inhibitors’. This search revealed 125 relevant references (entire Medline database up to 11 March 2014). The efficacy of tadalafil 5 mg once daily for the treatment of LUTS has been reported by several well-designed studies. Tadalafil improves significantly the total International Prostate Symptom Score (IPSS), the voiding and storage subscores, the IPSS Quality of Life (QoL) and the BPH Impact Index (BII). Its efficacy is irrelevant to the erectile function status of the patients. However, in the majority of these studies tadalafil is not associated with improvement in maximum urine flow or post-void residual volume (PVR). Its safety profile is well established and no new or unexpected adverse events other than those reported in ED studies have been recorded. Tadalafil is today a new treatment alternative to other established drugs for LUTS such as the α-adrenergic antagonists or 5α-reductase inhibitors. However, it is not just an alternative, since sexual adverse events associated with these drugs are avoided and tadalafil is the only drug that can treat both ED and LUTS at the same time.