The current investigation explores possible reasons for the poor overall success rates of medical techniques used in the treatment of erectile dysfunction. This is the first study to compare directly the psychological impact of a mechanically produced versus an erotically produced erection. Subjective and objective parameters of sexual arousal were used to compare the experience of a mechanically attained erection versus an erotically stimulated erection. Twenty-eight (28) men without sexual dysfunction were asked to reach a full erection during each of the following two conditions: (a) by using an ErecAid System and (b) by self-stimulating while watching an erotic video. The results of this study suggest that the penile vacuum device was a successful method for attaining penile tumescence; however, the presence of penile tumescence was not accompanied by a subjective state of physical or mental sexual arousal. Thus, the mere physical presence of an erection does not seem to evoke bodily or mental feelings of sexual arousal. It is important to note that these findings suggest that attention to the psychosexual components of the individual's sexual experience are critical to the subjective experience of sexual arousal and reflect once again the multimodal response systems involved in sexual arousal. These results suggest that more effective treatment approaches would be based on a clinical strategy that provides instruction both on the technical use of a mechanical device as well as on the importance of creating an appropriate psychosexual environment.