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 who respond to oral therapy (PDE-5 inhibitors). The current study will check the Efficacy and Safety of a Second Series of LISW Treatment for Erectile Dysfunction Patients Who Were Partial Responders to the Initial Treatment.

The patients will be selected out of the patients with Erectile Dysfunction who received Low intensity shock waves and Were Partial Responders to the treatment.

At the first meeting the patient will receive a full explanation of the study, the potential efficacy and risks. After that the patient will be asked to sign an informed consent form. The patient's general medical condition and any problems related to sexual dysfunction are already known from the previous study he was participating. Also the patient's sexual function is already known by sexual function questionnaires that were filled out in previous study. The criteria for inclusion and exclusion will be reviewed, as well as physical examination. Then shall the patient obtain reporting sexual encounter diaries (SEP) and will be asked to avoid using PDE5i's for a month (washout), if he did not do so of some reason after ending the previous study, then it would be the first visit (Visit 1). At visit 1 The patient will be questioning the sexual function questionnaires without PDE5i's and will pass examination performance Endothelial - FMD, the test takes about 10 minutes, it is not an invasive test (not involved in inserting an instrument or any medication) and is painless. The patient may be asked to also undergo Doppler ultrasound. At the end of visit 1 the patient will begin Series of 12 treatments, in which the subject will be treated twice a week for 3 weeks (6 treatments), then would be discontinuation of the study for 3 weeks, and at the end of this period will be treated twice a week for 3 weeks (6 treatments). Four weeks after the treatment series ends the patient will come for another visit and will be asked to fill in questionnaires and perform the FMD and/or Doppler ultrasound test again. The patient's ED condition will be followed up for a long term after the end of his participation in the study.

Inclusion Criteria:

1. Incomplete response to active treatment (not placebo) on first round but patient is still unsatisfied.
2. Recurring ED (had improved on first round of shock wave therapy but after a certain period of time became clinically worse again) after shock wave therapy.
3. A minimum of two sexual attempts per month.
4. An IIEF-ED domain score ≤ 25 post screening, with or without PDE5i intake according to assessment on final visit of Shockwave previous treatment.
5. A stable heterosexual relationship with the same partner for more than three months

Exclusion Criteria:

1. Subjects that did not respond at all to the first round as well as those that did not respond sufficiently.
2. Any pelvic surgery during the period after the first round.
3. Any unstable medical or psychiatric condition, spinal cord injury, or penile anatomical abnormalities arising during this period .
4. cardiovascular conditions that prevent sexual activity.
5. Recent Use of anti-androgens, or oral or injectable androgens
6. Recent hormonal, neurologic, or psychological pathology