The purpose of this study was to evaluate and anticipate the outcome of daily use of tadalafil in patients with erectile dysfunction using elastography. 183 volunteers and 183 patients with erectile dysfunction were included. Pretreatment SWE readings for our patients were calculated with a linear probe. IIEF score Q was measured once at the start of the study for volunteers and twice for patients, one prior to the start of tadalafil administration and the other on one year of 5 mg daily tadalafil after the second post-washout (one month post-treatment stopped). There was no significant difference between patients and volunteers in mean age or risk factors except in SWE values as mean SWE of volunteers was 14.03 ± 1.54 kpasc, while mean SWE of patients was 21.278 ± 8.228 kpasc. The presence of comorbid diabetes, severe disease and pre-SWE ≥23.635 was significantly associated with poor outcome. We conclude that penile SWE could be useful to select probable good responders for a continuous tadalafil use, thus avoiding the unnecessary cost and time in non-responders.