The aim of this double-blind study was to explore the pain-alleviating effect of low energy laser in lateral epicondylalgia. Forty-nine patients were consecutively assigned at random to two groups, laser or placebo. The Mid 1500 Irradia laser was used with the following parameters: wavelength 904 nm; average power output 12 mW; peak value 8.3 W; frequency 70 Hz (pulse train 8000 Hz). The laser (Ga-As) was locally applied to 6 sites on and around the epicondyle. Each point was treated for 30 sec, resulting in a dose of 0.36 J/point and an area of treatment of 0.2 mm2. Patients were treated 2-3 times weekly, for a total of 10 treatments. Follow-ups were done after three and 12 mo. The statistical analysis showed that the laser treated group had a significant improvement in some objective outcomes after the treatment period and at the 3 mo follow-up, but there were no significant differences in the subjective outcomes between the groups. Irradia laser treatment may be a valuable therapy in lateral epicondylalgia, if carried out as described in this study. However, further studies are necessary before low energy laser can be employed as a pain-relieving method.