PURPOSE: to verify the existence of an association between the degree of spasticity, the level of motor function and wide topographical classification of CP children with amplitude and time parameters of electromyographic activation of temporalis (AT) and masseter (MA) muscles. METHODS: muscle activity during chewing task was evaluated in fifteen children with CP. The clinical instruments used were the Modified Ashworth Scale for spasticity, the Gross Motor Function Classification System (GMFCS) for gross motor function. We analyzed the parameters of muscular symmetry and time of active and inactive period of the masticatory cycle. RESULTS: there was an association between the level of motor function and the symmetry of the MA, between the highest degree of spasticity and decrease in the inactive period and increase in the active period of the masticatory muscles and between the topographical classification and symmetry of the MA and the symmetry of the AT. CONCLUSION: the symmetry and the time of activation of AT and MA should be considered during therapy of oral motor function of CP children.