A review. The epidemiol. and current clin. treatment of benign prostatic hyperplasia (BPH) and erectile dysfunction (ED) were reviewed in this paper. The publications from PUBMED and CNKI were retrieved and analyzed, and four conclusions were made as followings: 1. Both BPH-LUTS (benign prostatic hyperplasia-lower urinary tract symptoms) and ED were highly prevalent in aging men and the incidence of both diseases increased consistently with age. New data indicated that both diseases potentially shared common pathophysiol. mechanism. 2. Although each of the diseases has first-line treatment resp., PDE-5 inhibitors showed great efficiency in both indications. 3. The marketed drugs for BPH and ED showed different adverse effects, such as retrograde ejaculation caused by Tamsulosin, mammary glands hyperplasia caused by Finasteride and vision disorder caused by Sildenafil. 4. Currently marketed PDE-5 (Phosphodiesterase 5) inhibitors lack the optimal profile in term of the selectivity and PK (Pharmacokinetic) properties. In a word, NO (Nitric Oxide) signal pathway plays an important role in the pathophysiol. of both BPH-LUTS and ED. There is a great market prospect of applying PDE-5 inhibitors on BPH-LUTS, ED and their coincidence, and safer and more effective drugs for both conditions are highly needed to answer unmet medical needs.