With horseradish peroxidase and Phaseolus vulgaris lectin as tracers, a direct connection between the jaw closing parts of the ipsi- and contralateral motor trigeminal (Mo5) nuclei of the rat is shown. The contralateral projecting cells in Mo5 were small (18 X 11 microns) ovoid and bipolar. It is speculated that these contralateral projecting cells in Mo5 are interneurons that are involved in the coordination of the bilateral activity of jaw closing motoneurons during orofacial motor behavior.