ABSTRACT Objective: to verify if the chewing side preference interferes in the postural muscular electrical potential. Methods: fifty-five volunteers (41 women and 14 men; average age of 26 years) were evaluated by Odontology (determining the type of dental occlusion), by a speech therapist (determining the chewing side preference) and by a physiotherapist (evaluating the postural muscular electrical potential). The three professionals had no communication regarding the evaluations, in order to keep the study partially blind. For chewing preference electrognatography was used for muscles: sternocleidomastoid, upper trapezium, gluteus medius and tibialis anterior, bilaterally, in static orthostatic posture. Results: there was statistical significance for the muscular electrical potential of the sternocleidomastoid and anterior tibial, when there was right chewing preference (p=0.030 for both) and left chewing preference (p=0.0028 and p=0.0020, respectively). In alternate bilateral chewing there was tendency to symmetry of postural muscular electrical activation, in all muscles. Conclusion: there was presence of asymmetry of postural muscular electrical activation in the sternocleidomastoid and tibialis anterior, when chewing side preference was at right or left. In the presence of alternate bilateral mastication, there was tendency of symmetry of postural muscular electrical activation for all studied musculatures.