Crazing in styrene-acrylonitrile copolymer (SAN) layers of polycarbonate (PC) / SAN microlayer composites and the deformation zone that formed in the PC layer in response to the stress concentration created at the PC/SAN interface by the craze tip were examined by optical and scanning electron microscopy. A 49-layer composite with relatively thick layers, on the size scale of tens of microns, was chosen in order to confine interactions to the region of a single PC/SAN interface. The SAN craze density, which increased with applied stress, was shown to fit the Weibull distribution function. The distance between crazes was described by a correlation length, and the distribution of correlation lengths indicated that crazing occurred randomly in the SAN layers. In the PC layer, the craze-tip deformation zone consisted of a colinear plastic zone together with a pair of micro-shearbands that grew away from the craze tip at an angle of about 45-degrees. Assuming a blunted craze tip, the plastic zone was analyzed using the slip-line field theory. The dependence of the micro-shearband length on remote stress was similar to that predicted by both the BCS and Vitek models.