Low intensity shock waves (LISW) have been proven in animal studies to induce local growth of new blood vessels. The investigators hypothesized that LISW therapy could improve the symptoms of patients with erectile dysfunction resulting from a problem of blood supply that do not respond to oral therapy (PDE-5 inhibitors).

In this study Low intensity shockwaves (1/10 the ones used in Lithotripsy) are delivered directly to the penile tissue using a specially designed shockwave device and probe. Shock wave therapy is applied twice a week for three weeks , then a 3- week interval with no therapy followed by another 3 week period of twice a week shock wave therapy. Before and after sexual function questionnaires and objective measures of erectile function will be performed.

Inclusion Criteria:

• ED of more than 6 months
• Rigidity score < 3 during PDE5i therapy
• SHIM <21 during PDE5i therapy
• Non- hormonal, neurological or psychological pathology Stable heterosexual relationship for more than 3 months

Exclusion Criteria:

• Prior prostatectomy surgery
• Any unstable medical, psychiatric, spinal cord injury and penile anatomical abnormalities
• Clinically significant chronic hematological disease
• Anti-androgens, oral or injectable androgens
• Radiotherapy in pelvic region