This study describes a 12–24 month follow-up on 119 ED patients in an attempt to understand satisfaction with and dropout from ICI use. Results indicate 40% attrition, attributed primarily to a lack of efficacy of ICI, but also to spontaneous return of erectile function and to negative reactions surrounding the injection procedure. Multivariate analyses indicated that ICI dropouts were more likely to have co-existing premature ejaculation, low responses during psychophysiological screening, a lack of spontaneous erections prior to ICI, and an etiology that included an organogenic component. These same factors, along with low satisfaction with their sex life, were related to attrition due specifically to a lack of drug efficacy. In contrast, attrition due to recovery of spontaneous erections was associated with high sexual satisfaction. Among ongoing users, dissatisfaction was associated with higher age, shorter erections during ICI use, and low satisfaction with sex life. These findings identify a number of factors related to attrition and satisfaction, emphasizing the importance of specifying the cause for ICI attrition and, demonstrating that a substantial portion of patients who dropout do so for positive reasons.