To determine the scoring resistance of spur gears with various coatings, scoring tests on gear pairs coated with copper, graphite, molybdenum disulfide and phosphate were carried out under forced lubrication using a power-circulating gear machine. Further, the surface temperature of a coated gear tooth was calculated. From the experimental results it was found that the effect of copper and molybdenum disulfide on the scoring resistance of the gears was significant and gears, of which the load-carrying capacity with no scoring was considerably large, could be developed. The order of the calculated surface temperature for scoring of the gears agrees with that of the scoring resistance of the gears.