Flowforming is an incremental forming technique which is used to manufacture seamless tubes with high precision and surface quality. Internal gear flowforming process (IGFP) is an interesting topic in which there is no need for costly tooling and high forming forces. In this research, the formation of internal gears byflowforming and the effects of process parameters on built-up edge are investigated and then optimized. First, the process is analyzed and simulated. Second, several controlled tests are accomplished to verify the simulationresults. Third, the effects of feed rate, thickness reduction percentage, attack angle, and roller diameter, on builtup edge are obtained using design of experiments procedure (DOE). Fourth, simulated annealing (SA) algorithmand genetic algorithm (GA) are used for optimizing built-up edge. According to DOE, the most significant parameters affecting the built-up edge are: attack angle, thickness reduction percentage, and feed rate. The builtupedge increases with increasing the attack angle, feed rate and thickness reduction percentage. Optimization results show that the minimum value of the built-up edge is equal to 0.449 mm in SA and 0.445 mm in GA.