Is androgen treatment sufficient to improve erectile function in patients with testosterone deficiency syndrome? Objective: In this article we propose that other treatments for erectile dysfunction should be added to testosterone if androgen treatment is insufficient to improve erectile function in patients with testosterone deficiency syndrome (TDS), since there are usually other concomitant disorders that could also cause the dysfunction. Material and methods: Between August 2007 and December 2009, 80 patients were diagnosed with TDS. Of these, 66 were treated with 50 mg of testosterone gel. All patients were examined at baseline and at 3, 6 and 9 months. General analytical parameters, albumin, total testosterone and sex-hormone binding globulin to calculate free testosterone levels were determined and the Aging Male's Symptoms (AMS) questionnaire and the International Index of Erectile Function (IIEF) were administered at these intervals. Results: Changes in calculated free testosterone was appropriate throughout the treatment, but not those in the AMS questionnaire (baseline: 44.06; 3 months: 37.4) or the IIEF domain (baseline IIEF: 10.98; 3 months: 15.4). Due to these results, concomitant treatments for erectile dysfunction were added. AMS decreased to 33.6 at 6 months and to 30.46 at 9 months. The IIEF domain increased to 19.08 at 6 months and to 22.40 at 9 months. Conclusions: TDS patients have comorbidities that alter erectile function. Therefore, specific treatments for erectile dysfunction should be added to testosterone. Some patients may not require this additional treatment in the future and may continue with testosterone alone.