Considering the multifactor aspect of TMD, studies are needed to establish effective forms of treatment. Thus, the following is the research question of the proposed study: Is phototherapy capable of reducing pain and influencing skin surface temperature over the masseter and temporal muscles in patients with TMD? Study Design: A randomized, placebo-controlled, double-blind study is proposed. Sample: Thirty-six women will participate in the study and will be allocated to two groups (18 per group) through a randomization process involving the use of opaque envelopes containing cards stipulating to which group each participant will belong: Group A (39.27 Joules) and Group B (0 Joules). Evaluation Procedures:  Diagnosis of TMD (RDC/TMD), Classification of TMD (FONSECAINDEX), Pain intensity (VISUAL ANALOG SCALE), Pain pressure threshold (ALGOMETRY) and Skin surface temperature (INFRARED THERMOGRAPHY). Intervention Procedures: A portable, nine-diode cluster phototherapy device (PainAway®, MultiRadiance Medical®, Solon, OH, USA) will be used for the administration of phototherapy. Phases of Study: Initial evaluation, Treatment, Immediate evaluation, 10-minute evaluation, 20-minute evaluation and 30-minute evaluation. Data Analysis: Pain, based on the VAS and algometric scores, will be the primary outcome and skin surface temperature will be the secondary outcome.