Abstract: An artificial kidney comprising a haemodialyser (a) associated with and preferably integrated into a common unit D adapted to be connected simultaneously to a patient P, to a container 34 of fresh and/or used dialysis liquid, and to a controlling and checking console (h). The disposable common unit can perform all the functions necessary for a treatment. These functions are not performed by self-contained members, but by a small number of flexible multifunctional parts, such as elements 14 and 15, each cooperating with rigid parts such as parts 10, 11, 12 and 13.