Objective: To evaluate the efficacy of low intensity laser therapy (LILT) as a monotherapy in two different regimens with exercise therapy in comparison to only exercise in the treatment of Myofascial Pain Dysfunction Syndrome (MPDS)  Subjects and Methods: A total of 60 patients with MPDS were included in the study and were randomly divided into three groups: The routine exercise was assigned for the first group (Control).The other two groups received LILT applied to the predetermined five most painful trigger points using two different protocols of  parameters. The following parameters were used for the second group (Group II): wavelength = 870 nm, power = 60 mw for 40 seconds., spot size = 0.55 cm² and energy density = 4.36 J/cm² per point, In the third group (Group III) the following parameters were used: wavelength = 870 nm, power = 60 mw for 90 seconds, spot size = 0.55 cm² and energy density = 9.82 J/cm² per point.  Results: Significant reduction in pain at rest and pain on movement was observed with all three types of treatment modalities. Pain reduction was significantly higher in those patients who received the regimen applied in Group III, with statistically significant decrease in the muscle tenderness and increase in maximum mouth opening with the same test group compared to the other two groups by the end of the experiment.   Conclusion: Application of LILT using these parameters: wavelength = 870 nm, power = 60 mw, spot size = 0.55 cm² and energy density = 9.82 J/cm² per point; for 90 sec. can be efficiently used as a monotherapy for the treatment of MPDS.