The purposes of this study were to compare the pain alleviating effects of laser treatment and placebo in tennis elbow. Also, the effects of laser radiation on the radial sensory nerve conduction, and the temperature changes in the tissue surrounding the treated radial nerve were studied. The results show that laser treatment is not significantly better than placebo in treating tennis elbow. Furthermore, no significant change was noted in the evoked sensory potential as well as subcutaneous temperatures in either experimental or control groups as a result of the applications of the laser radiation treatment.