In this paper, the cold simultaneous toothing of spur gears has been investigated. This method can be described as a press-rolling process. The influence of gear geometry such as teeth number and the deformation mechanism was investigated by 3D finite-element analysis using forge® software in terms of teeth forming and forming loads evolution. Based on these simulations, the experimental investigations were carried out to obtain a spur gear form with the good quality, using several billet dimensions. The experimental trials and simulations conducted for the spur gear (z = 23 teeth and m = 1.5 mm) showed premises to continuous flow lines formation at the base of the teeth. The maximum pressing force results from the numerical simulation agree with the experimental maximum force recorded.