The current paper is principally dedicated to the study of geometry and frequency effects for internal spur gears heated by induction. The overall work is realized by the simulation efforts performed on Comsol multi-physics software. The 3D model used during this study is built basing on coupling between Maxwell’s and heat transfer equations. This model is used to calculate the temperature profile in the gear in function of machine parameters. The module and the frequency are varied to determinate their effects. In fact, two gears having the same external diameter but different modules are exploited during this study and the frequency is varied from low to high level. The obtained results allow understanding the effect of module and frequency on the final temperature distribution. Finally, the optimal frequency value permitting to have the best temperature profile is found.