Erectile dysfunction is a prevalent disorder that not only affects men with the disorder but also their partners. Significant improvements in the sexual health of these couples have been achieved with the introduction of phosphodiesterase 5 (PDE5) inhibitors. Currently PDE5 inhibitors are used on an on-demand basis. New evidence regarding the effects of PDE5 inhibitors on the underlying pathophysiologic processes that cause erectile dysfunction have sparked interest in the continuous dosing of these medications. We will discuss the biological background and the available clinical evidence for the continuous use of phosphodiesterase inhibitors in erectile dysfunction. Lastly, we will discuss the emerging clinical data for the use of daily PDE5 inhibitors in men with lower urinary tract symptoms.