The inventive modular gear system consists of two or several gear modules (1-3) of the same or different designs, said gear modules in turn comprising one or several gear sizes, and one or several transmission ratios within one size. At least one of these gear modules is an angular gear (3). The inventive gear system also comprises one or several drive modules (4, 5) which can be combined therewith as required, the relevant drive unit of a drive module (4 or 5) having a cylindrical output pinion corresponding to the relevant transmission ratio. The aim of the invention is to simplify at least one gear module in a modular gear system of this type, more precisely, an angular gear (3), without reducing the capacity of the entirety of the gear modules(1-3) to combine with the entirety of the drive modules (4, 5). To this end, the one angular gear (3) or at least one of the angular gears is a contrate gear whose contrate wheel is adapted for engaging the corresponding output pinion (7).