Aim of the study : To evaluate the effectiveness of low level laser therapy for the control of TMJ pain. Materials and Methods: This study included 12 patients with clinical diagnosis of DDWR in a random and double blind research design. Patients, divided into study group and control ( placebo) group submitted to treatment with LLL using Ga-As diode laser. Study group received 3 sessions per week during 4 consecutive weeks while placebo group received inactive laser using the same technique and schedule as study group. Results: There were not statistically significant differences between both groups.