Introduction. Erectile dysfunction (ED) is more prevalent with increasing age. Previous studies showed that ED was negatively associated with mental health (MH) in specific patient groups. Aim. To examine the association, and potential mediating factors, between ED and MH in healthy elderly men. Main Outcome Measures. ED was defined as (almost) always having problems in achieving or maintaining an erection if desired, or not being sexually active because of erectile problems. MH was assessed with 36-item Short-Form Health Survey scale MH5 with five items on, e.g., being happy or depressed (range 0-100). Potential mediators between ED and MH were satisfaction with and importance attached to sex life. Methods. The study population consisted of a consecutive sample of 3,810 participants from the European Randomized Study of Screening for Prostate Cancer, aged 57-78 years, who had screened negatively for prostate cancer. Associations between ED, potential mediating factors, and MH were tested by analysis of variance and analysis of covariance. Results. Covariance analysis, adjusted for age, comorbidity, and use of erectile aids, showed that men with ED had significantly lower MH scores (80.8 ± 1.2) than men without ED (83.7 ± 1.2; P < 0.001). ED was also associated with the potential mediator "satisfaction with sex life" but not with "importance attached to sex life." Men with ED were significantly more often dissatisfied with their sex lives (P < 0.001). Adjustment for satisfaction with sex life, but not for importance attached to sex life, reduced the strength of the association (β value) between ED and poor MH from 2.88 to -0.84. Conclusions. ED was associated with poorer MH. Satisfaction with sex life, but not importance attached to sex life, may play a mediating role in this association. These results suggest that if men with ED can be helped to be satisfied with their sex lives despite ED, MH can be preserved.