Sildenafil citrate is an effective oral drug for erectile dysfunction. The main action of sildenafil is the enhancement of the effect of nitric oxide (NO) by inhibiting the cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase-5 (PDE-5), an enzyme responsible for degradation of cGMP. NO is also present in the nasal mucosa and is responsible for vasodilation causing congestion and nasal obstruction. The aim of this study was to detect the effect of sildenafil on nasal mucosa in terms of nasal obstruction. A total of 16 patients presented to urology clinic suffering from impotence and medicated with sildenafil were included in the study. Before and after oral administration of 50 mg sildenafil, in all of the patients the nasal patency was examined by active anterior rhinomanometry (a method of assessing nasal resistance) using air pressure of 150 Pascal. In addition, all patients were asked about their sensation of nasal patency to detect the symptomatic nasal obstruction. There was a significant decrease in nasal air flow values (cm(3)/s) (p < 0.05). Except for three cases, all patients indicated that they had the sensation of nasal obstruction after the use of sildenafil (p < 0.05). Nasal obstruction is a common complaint for the patients using Sildenafil.