The main objective of this project is to design a new gearbox for an electric Formula SAE car. The last car had one motor for each wheel, and for the new car, only one motor will be used to give traction to the rear wheels. The gear selection has been done by using the Optimum Lap software. Which after giving the main parameters of the car as well as the geometry of the circuit, returns the data needed to design the powertrain system, among others. A comparison haas been done between the different transmission systems available. After deciding that the use of a gearbox is the best option, another comparison has been done to choose the type of gears. To do so three different basic designs have been done with CATIAV5. The selected option is to use three stage spur gears. To design the tooth form, materials and shaft-hub conection selection, the KISSSOFT software has been used. To optimize the different parts after designing them with CATIAV5, the parts have been meshed with HyperMesh and processed in Abaqus. The final design weights less than 6kg and contains all the parts needed inside of the gearbox. The connections to the motor or the wheels have not been designed.