The bending and surface stress of the gear tooth is considered to be one of the main contributorsrnfor the failure of the gear in a gear set. After the investigation of shot peening to increase therntooth bending strength and surface durability in gears, the surface roughness generated duringrnshot peening leads to macro and micropitting is now considered the dominant restriction on gearrnlife and performance. Thus, analysis of stresses has become popular as an area of research onrngears to minimize or to reduce the failures and for optimal design of gears. This thesisrninvestigated the effect of tooth parameters monitoring the stresses induced on spur gear byrnoptimizing face width, root fillet radius, and number of teeth relative to weight of spur gear set.rnThe involute profile of Spur gear has been modeled and the simulation was carried out for thernbending and contact stresses. To estimate bending and contact stresses, 3D models wererngenerated by modeling software CATIA V5r16, simulation was done by finite element softwarernpackage ANSYS 12.0, and optimization was done using Design Expert Dx7 numericalrnoptimization method. Analytical method of calculating gear bending stresses uses Lewis andrnAGMA bending equation. For contact stresses Hertz contact equation are used. The Study wasrnconducted by varying the face width, number of teeth and root fillet radius to find its effect onrnthe bending and contact stress of spur gear. It was therefore observed that the maximum bendingrnstress and contact stress decreases with increasing face width, number of teeth and root filletrnradius relative to spur gear set weight. Using the Design expert software Dx7 the optimal pointsrnwere selected at face width 37.24mm, root fillet radius 3mm, and number of teeth 22.At thesernvalue contact stress was reduced from 389.31Mpa to 294.56Mpa (24.34%) and bending stressrnwas reduced from 105.14Mpa to 49.65Mpa (52.80%).So that, it is recommendable to use optimalrnvalues of tooth parameters during design work to reduce stresses. It means stress reductionrnresults in better tooth root load capacity, micropitting resistance, prolongs gear service life.