Introduction Erectile dysfunction (ED) is frequently observed in end-stage renal disease (ESRD) patients on hemodialysis (HD) compared to non-uremic patients. This situation causes severe psychogenic problems in patients and disrupts the quality of life. Different phosphodiesterase type 5 (PDE-5) inhibitors have been used, and efficacies revealed, for the treatment of ED in HD patients; however, there are no studies related to udenafil use or results for HD patients. This study retrospectively evaluated the efficacy and reliability of udenafil for HD patients. Materials and methods The laboratory findings, side effects after treatment, and International Index of Erectile Function (IIEF) scores before and after treatment were compared and evaluated for HD patients who applied to our urology clinic with ED complaints and were treated with udenafil. Results The results showed that in the HD patient group with ED, apart from ED, there were severe rates of other sexual dysfunction. In our patient group, there was a statistically significant improvement in all scores for erectile function (p=0.033), orgasmic function (p<0.001), sexual desire (p<0.001), relationship satisfaction (p<0.001), and general satisfaction (p<0.001) after treatment. The reported side effects were headache in one patient and dyspepsia in one patient. Conclusion We concluded that udenafil is an effective and reliable treatment approach for HD patients; however, our results require support from prospective randomized crossover studies with sildenafil.