Sildenafil has had a dramatic influence on the field of sexual medicine over the past 20 years. Not only have phosphodiesterase-5 (PDE5) inhibitors improved the treatment of erectile dysfunction (ED), they have indirectly contributed to the treatment of male factor infertility. A review of the literature between 1998 - 2018 was performed using PubMed with regards to sildenafil and male infertility. Numerous studies have demonstrated sildenafil's safety and efficacy for treating ED. Sildenafil does not alter semen parameters, and, in fact, may positively affect semen parameters. Sildenafil is helpful for treating ED caused by the psychological stress of infertility treatments. Sildenafil has improved the treatment of ED and may have a benefit on semen parameters. This has aided in the management of male factor infertility, and has contributed to hundreds of thousands of pregnancies that would have been more difficult, as it was before its advent.