Abstract: The process for measuring the coefficients of adhesion and friction of a drilling fluid involves, following the standardized filtration of the drilling fluid or mud from which a solid phase "filtration cake" and a liquid phase or filtrate collected on the downstream side of a filter 15 are obtained, placing a metal piston skirt 29 in contact with a filtration cake in the presence of a contact pressure, and measuring the moments of adhesion and friction when the skirt is driven in axial rotation perpendicular to the contact surface, and the axial extraction or contact adhesion force when the skirt is withdrawn after a determinate period of contact.