OBJECTIVE A study comparing intracorporeal injection of prostaglandin E1 (one-drug solution) and papaverine plus prostaglandin E1 (2-drug solution) for treatment of impotence. METHODS A total of 100 impotent patients had intracorporeal injections of the one-drug and 2-drug solution alternatively in 3 sessions. The quality and duration of erections were assessed. RESULTS Seventy-five per cent of the patients developed full erection with the 2-drug solution compared to 50% with the one-drug solution. The average duration of erections was 60 minutes and 45 minutes, respectively. The complication rate was higher for the 2-drug solution. CONCLUSIONS Papaverine plus prostaglandin E1 is superior to prostaglandin E1 alone for treatment of impotence, but has a higher rate of complications. Intracavemous injection of vasoactive drugs is a very effective and important way for treatment of impotence. Papaverine plus prostaglandin E1 had been used for treatment of impotence alone or combined. A blind study was done to compare efficiency and complication rates of intracavemous injection of papaverine plus prostaglandin E1 (2-drug solution) with prostaglandin E1 alone.