This document specifies a method for the determination of the adhesive strength of a vulcanized or thermoplastic rubber bonded to a rigid substrate, using a test piece comprising a strip of rubber bonded to a single plate of rigid material. The test is carried out at a peel angle of 90°. The method is applicable primarily to test pieces prepared in the laboratory under standard conditions, such as can be used to provide data for the choice of rubber compounds or adhesive systems, the development of such materials and the control of manufacturing processes. This method is not suitable for high-hardness rubbers, typically above 85 IRHD.