Pitting and scoring is a phenomenon in which small particles are removed from the surface of the tooth due to the high contact stresses that are present between mating teeth. After the investigation of shot pinning to increase the tooth bending strength in gears, surface durability, in the form of macro and micro-pitting, is now considered the dominant restriction on gear life and performance. In this book a method is develop to study surface fatigue in involute spur gears using finite element analysis. In achieving this two-dimensional & three-dimensional equivalent contacting cylinders & three-dimensional model of involute spur gear is used. The modeling is done using finite element computer package, ANSYS & solid modeling software, CATIA. In this book effect of loading condition and material types in contact stress in gears, estimation of surface fatigue in rolling-sliding contact condition in spur gear, effect of initial surface roughness on surface fatigue is studied. The results obtained are compared with analytical method.