Abstract: There is disclosed a mixing and kneading device for processing material such as synthetic plastics material. The device, which is designed primarily for use in a laboratory or for research and development work, consists of a power drive unit and a work unit. The work unit comprises a receptacle and is composed of a part adjacent to the drive unit and a part remote from the drive unit for placing thereinto a supply of material to be processed. Suitable mixing and kneading tools are journalled within the receptacle and releasably coupled to the power drive unit. The two receptacle parts are locked by an easily releasable clamping means to each other and to the power unit. Release of the clamping means selectively releases only the remote part of the receptacle or both parts from the drive unit, thereby permitting convenient and rapid emptying and cleaning of the receptacle, and also of the kneading and mixing tools after completion of a processing operation.