The macroscopic cavitation and yield behaviour of nylon-6/rubber blends was studied. The type of rubber (poly(butadiene), ethylene propylene copolymer (EPDM) or polyethylene (LDPE), the rubber concentration and the rubber particle size was varied. The onset of cavitation was determined by measuring the intensity of the transmitted light from an incident laser beam. Both the yield stress and the cavitation stress appeared to increase with increasing strain rate and rubber modulus. No linear relation between the shear modulus and the cavitation stress was found. The data indicate that blends with a very small particle size have a relatively high cavitation stress. In all cases, a high cavitation stress of the elastomer resulted in a high yield stress of the blend.