A study of the bending stresses in a pair of meshed spur gears using the finite element method is presented. The models analyzed were in the shape of a circular gear with five teeth or a five-tooth rack. A unit torque (1 lbf-ft) was applied as the form of nodal forces on the nodes around the bore hole of the driver pinion. The nodes around the bore hole of the driven gear (or the nodes along the back of the driven rack) were fixed. In order to transmit the power from the driver pinion to the driven gear (or rack), the points in contact were made coincident. Seven model groups with same diametral pitch (1.0), addendum (1.0 in.), dedendum (1.3 in.), pressure angle (20°) and hob tip radius (0.35 in.) but with varying numbers of teeth on the pinion and gear were analyzed to compute the tensile stress variation in the root fillet during the duration of contact. A model for predicting the tensile stress variation at the root fillet during the duration of contact has been created. The results were compared with AGMA and other results with agreement for the peak within 3%. / M.S.