Mechanisms of wet abrasion for nitrile rubber have been investigated using a Din-disc-type test machine. Rubber specimen was held against rotating steel disc. Both the speci-men and the disc were immersed in an abrasive liquid of the type used for oil well drilling. It is concluded that wear occurs as a results of two different mechanisms: local micro tearing process and a general micro-layering or micro-polish-ing process. Rates of wear were found to increase with the applied frictional force raised to a Dowern and to be propor-tional to a neqative Dower-bof the coefficient of friction.