Introduction <p>Erectile dysfunction (ED) is commonly observed in Type 2 diabetic men, affecting approximately 75% of this demographic. Evidence suggests that phosphodiesterase-5 (PDE-5) inhibitors have limited therapeutic effects on progressive ED in men with Type 2 diabetes, indicating the need for alternative treatment lines. This study aims to investigate the effects of testosterone therapy on ED in Type 2 diabetic patients with normal testosterone levels.</p> Materials and methods <p>This single-blind randomized clinical trial was conducted on Type 2 diabetic men with normal testosterone levels and erectile dysfunction. The control group received standard treatment with tadalafil 20&#xa0;mg two hours before intercourse. In contrast, the intervention group, in addition to tadalafil, received 250&#xa0;mg of intramuscular testosterone at 3 points (the start, and at 1 and 2&#xa0;months afterwards. Informed consent was obtained, and participants were selected based on inclusion and exclusion criteria.</p> Findings <p>A total of 60 Type 2 diabetic patients with ED were included, with an average age of 50.4 ± 9.7&#xa0;years. Significant differences were observed between the intervention and control groups in terms of average total testosterone and International Index of Erectile Function (IIEF) scores (<i>P</i> value &lt; 0.01), with the intervention group showing higher averages. These differences were also significant over time (P value &lt; 0.01), indicating improved outcomes concerning the baseline.</p> Conclusion <p>Testosterone therapy in diabetic men led to improvements in sexual desire and ED without adverse effects on liver function.</p>