A conveying system for agricultural machines, comprised a housing, and a modular conveying mechanism configured to be introduced into the housing and to be detachably connected thereto, wherein the conveying mechanism is provided with drive mechanisms and guide mechanisms. The conveying mechanism includes an endless conveyor that rotates about the drive mechanism and the guide mechanism. The conveying mechanism is provided with a self-supporting frame structure in which the drive mechanisms and the guide mechanisms are rotatably mounted.