The aim of this work was to evaluate the efficacy of sodium nitroprusside (SNP) in management of erectile dysfunction in a clinical comparative study with papaverine I phentolamine (control drugs) in erectile dysfunction patients. Forty patients with erectile dysfunction (ED) were randomly assigned to receive 300 ug of SNP, then after one week received control drugs (papaverine 30 mg and phentolamine 1 mg), intracavernously and vice versa. The patients were divided into two groups. Group I: included 20 patients, 32-48 years old, complaining of ED. Group II:Included 20 patients, 31-6 years old, complaining of ED.There was no significant difference between erection induced by SNP and control drugs, but there was and 8 patients developed prolonged erection (erection more than 4 hours) when receiving the control drugs, but not a single one after receiving SNP. SNP facilitates relaxation of penile smooth muscle and penile erection without significant side effects, SNP may be used in erectile dysfunction patients that experience pain and priapism with papaverine I phentolamine (control drugs).