In this work, microcellular ABS foams were studied. A series of injection molding samples defined by a design of experiments was carried out to analyze the effect of shot volume, mold temperature, and injection velocity on the morphology, mechanical properties, and surface roughness of microcellular samples. A predominant influence of shot volume on the cell structure and tensile properties was evidenced. Higher cell densities and narrower cell size distributions were obtained at lower injection volume. However, elastic modulus and tensile strength were improved by increasing the shot size. The effect of mold temperature and injection velocity was secondary. Higher levels of mold temperature and injection rate provided finer cell morphologies, but their effects on the elastic modulus and tensile strength were negligible. The decrease in shot volume and increase in gas content led to poor surface quality, whereas it was greatly improved by raising both mold temperature and injection velocity