Objectives: To evaluate the effect of bio-electromagnetic energy regulation (BEMER) therapy on erectile dysfunction (ED) in patients with multiple sclerosis (MS). Methods: A triple-blind randomized clinical trial was conducted in two different centers. Fifty-two male participants with MS were randomly allocated into two groups. Patients received either three weeks of BEMER with pelvic floor exercises or sham BEMER with pelvic floor exercises. The primary measure was the International Index of Erectile Function—Erectile Function (IIEF-EF). Secondary measures included the Sexual Health Inventory for Men (SHIM), Erection Hardness Scale (EHS), Arizona Sexual Experience Scale (AXES), Modified Fatigue Impact Scale (MFIS), and Multiple Sclerosis, Intimacy, and Sexuality Questionnaire (MSISQ-19). Results: Compared to the sham BEMER group, the BEMER group showed better improvements in the IIEF-EF (mean difference [MD]: −6.9, p < 0.001), SHIM (MD: −6.1, p < 0.001), EHS (MD: −0.4, p = 0.022), AXES (MD: 2.9, p = 0.030), MSISQ-19 (MD: 15.0, p < 0.001), and MFIS (MD: 31.0, p < 0.001). Conclusions: BEMER therapy improved erectile function and sexual satisfaction and reduced fatigue in patients with MS after three weeks of intervention. Long-term follow-up studies are warranted to ascertain the sustained benefits of BEMER therapy for MS-related ED.