Abstract A morphological study of stress whitening in commercially available propylene(P)-ethylene(E) block copolymers with ethylene contents ranging from 8 to 18 wt-% has been carried out. The morphological features of these block copolymers were established by electron microscopy, x-ray diffraction methods, and differential scanning calorimetry techniques. P-E block copolymers are composed of two crystalline phases and a noncrystalline EPR phase. Molded sheets of copolymers were stress whitened through drawing and studied mainly by scanning electron microscopy. Globular particles of polyethylene are observed. An initial stage of whitening can be associated with craze-like textures initiated at these globular particle boundaries. Void cracks around particles are also formed as the extent of whitening is intensified through drawing. The influence of the globular particles and the effect of EPR component under stress whitening conditions in P-E block copolymers is described.