Abstract: A method for making gearmotors comprising a casing, a pinion and a gear, meshed with the pinion, both supported by the casing, comprises the steps of: preparing a mould for the casing; making the casing by casting in the mould; the step of making the casing consisting of a step of injecting a molten plastic material into the mould so that the casing is formed by the plastic material once it has cooled.