ABSTRACT Introduction The current management of vasculogenic erectile dysfunction is based mainly on getting an erection firm enough for sexual intercourse with pharmacologic treatment. Some studies have shown that shock waves improve erectile function and could be a way to treat the endothelium in the corpora cavernosa. Radial wave therapy is commercialized as an option for the management of erectile dysfunction. However, the mechanism of action of the radial waves differs substantially from shock waves, so the evidence gathered for shock wave therapy cannot be extrapolated, and are very few clinical trials with the radial wave. Objective To assess the efficacy and safety of radial wave therapy compared with sham therapy for the treatment of primary erectile dysfunction. Methods This was a randomized, double-blind, sham-controlled clinical trial. Eighty patients with moderate erectile dysfunction, without sickle cell anemia, anticoagulation treatment, comorbidities, or conditions associated with secondary erectile dysfunction were included. Patients were randomized 1:1 to one of two arms: 6 weekly sessions of radial wave therapy (RW group) or 6 weekly sessions of sham therapy (control group). The parameters for radial wave therapy were 1 weekly session, 4,000 pulses in the body of the penis in a sweeping technique and 2,000 pulses in the perineal area (bilateral ischiocavernosus and bulbospongiosus muscles) at 2.4 Bar and a frequency of 17 Hz. The sham therapy group received 6 weekly sessions under the same parameters of radial wave therapy, using an internal bar in the handpiece of the equipment to prevent the patient from receiving the wave. All patients received sildenafil 20 mg. The efficacy and safety were assessed at 6 and 10 weeks after randomization. The primary outcome was the mean change in the International Index of Erectile Function - Erectile Function (IIEF-EF) domain score at 6 weeks after randomization. An intention-to-treat analysis was performed. Results Eighty men were randomized. The average baseline IIEF-EF score was 16.3 +/- 3.2, and the median baseline erection hardness score (EHS) was 3 (range, 1 to 3). At 6 weeks after randomization, the average change in the IIEF-EF score was 3.4 (95% confidence interval [CI] 1.5-5.2) in the RW group and 4.2 (95% CI 2.5-5.9) in the control group (p = 0.742). A total of 36.8% of the patients in the sham therapy arm and 41.7% of the wave therapy arm increased the EHS by at least 1 point at week 6 after the end of treatment (p = 0.671). At week 10, this proportion was 26.3% and 30.6%, respectively, for each group (p = 0.686). There were no changes in the dose of sildenafil in any of the groups. Non-serious adverse events occurred in two (5%) patients after radial wave therapy, and in one (2.5%) patient after sham therapy. Conclusions No difference was found in this study between men with erectile dysfunction treated with radial waves and men treated with placebo sham therapy.