In this study, the pitting formation of the tooth flank of concave-convex involute gears was investigated. The gears were manufactured from AISI 8620 steel with computer numerical control (CNC) machining and subjected to a cementation hardening process because they could not be produced using traditional methods. The results of the experimental studies with these gears were compared to those obtained with spur gears. As a result of this comparison, and because the pitch line of spur gears is less than the pitch line of concave-convex gears with exactly the same dimensions, the maximum Hertz stress formed in the pitch point of concave-convex gears is found to be less than that formed in the pitch point of spur gears. Therefore, the formation of pitting in concave-convex gears is quite delayed.