Background: Osteoarthrosis is a severe, evolutionary, chronic, and limiting disease that influences on quality of life, as it affects synovial joints and promoted degradation of hyaline articular cartilage. We sought to determine if electromyographic activity of the masticatory muscles and quality of life are negatively impacted by osteoarthrosis.Material and Methods: A sample of 72 participants between 40 and 70 years old diagnosed with osteoarthrosis were selected. Forty-eight participants met the inclusion criteria of this study and were divided into two distinct groups: with osteoarthrosis (n=24) and without osteoarthrosis (n=24). Electromyographic activity of the masseter and temporalis muscles (mandibular rest, right laterality, left laterality, protrusion, and dental clenching in maximal voluntary contraction) and quality of life measurements were used. Electromyographic activity was used to analyze muscle activation patterns. OHIP-14Br and SF-36 questionnaires determined the quality of life.Results: The participants with osteoarthrosis presented significant greater electromyographic activity (p?0.05) at rest for the right temporal muscle (p=0.04), maximum voluntary contraction for the left masseter muscle (P=0.04), repercussions of oral conditions on quality of life by the sum of OHIP-14 (p=0.002), and a statistically significant difference was found in all subgroups of the SF-36 scale between the subjects with and without osteoarthrosis (p?0.001).Conclusions: People with osteoarthrosis have changes in electromyographic activity of the masticatory muscles and quality of life compared to healthy participants.