272 patients with lateral epicondylitis who did not respond to at least 6 months of conservative treatment were treated with local anesthesia. They were then randomized to extracorporeal shock wave therapy with three treatments of 2000 pulses each or to placebo treatment. The primary outcome was rate of success (based on the Roles and Maudsley score and need for additional treatment) at 12 weeks. Other outcomes were the Roles and Maudsley score, subjective pain rating, and grip strength through 12 months. Success rates were similar between the two groups and there were no significant differences between groups for the other outcomes. Two-thirds of patients in both groups showed improvement at 12 months.