The damage zone development in poly(vinyl chloride) (PVC) and its transparent blends with methyl methacrylate-butadiene-styrene (MBS) core/shell rubber was studied as a function of temperature and rubber content in a triaxial stress state under slow tensile loading. Failure at the semicircular notch occurred by shear yielding followed by stress whitening. In unmodified PVC, the shear yielded plastic zone size was not affected by temperature in the range between -40 and 40 degrees C. In the blends, the plastic zone preceding stress whitening increased in size with temperature and rubber content, shifting the stress-whitened zone further away from the notch root. Below 0 degrees C, stress whitening initiated at the notch root and the stress-whitened zones had a crescent shape similar to those of PVC/CPE blends studied previously. In unmodified PVC, stress whitening initiated from the growth of preexisting microvoids at the tip of the shear yielded zone containing two families of curving slip lines emanating from the notch root. In contrast, stress whitening in the blends was more intense and was initiated by the cavitation of the rubber particles.