Erectile dysfunction (ED) is a common side effect to radical prostatectomies, even with nerve-sparing procedures. To ameliorate the problem so-called "penile rehabilitation" programs have been developed. The most widely used method of this is subscribing sildenafil or other PDE5-inhibitors to patients following surgery. This is based on a theory that these drugs may increase penile oxygenation and provide antiapoptotic factors (primarily NO and cGMP), thus protecting the penile tissue in a period with reduced nerve function following the surgery. Preclinical studies have confirmed the potential of sildenafil in this context and early human trials have suggested that a steady ingestion of sildenafil might protect the structural integrity of the penis. However, subsequent well-designed trials have not been able to confirm the initial findings. This fits well with sildenafil's mechanism of action because it does not actually induce erections or the production of either nitric oxide or cGMP. Rather, the drug enhances effects of an erectile response induced by neurotransmitters from the cavernous nerves. Therefore, sildenafil should no longer be offered as a sole means of penile rehabilitation. Rather, more research is needed, and clinicians need to apply a broader concept of sexual rehabilitation in postprostatectomy ED.