The susceptibility of various plastics to environmental stress cracking (ESC) was studied using a variety of agents in common use. It was found that styrenic polymers are susceptible to ESC by many kinds of agents, including detergents, that have non-ionic surfactants as their components. The ESC of acrylonitrile-butadiene-styrene (ABS) copolymer caused by non-ionic surfactants was studied intensively, and the dependence of crack propagation behavior on temperature and on the kind of non-ionic surfactants was investigated by edge crack tension (ECT) tests. The morphology at the crack tip of ECT specimens was investigated by a transmission electron microscope REM. It was found that crack propagation behavior was closely related to the morphology at the crack tip and the morphology was affected by temperature and type of surfactants. The change in morphology at different experimental conditions was attributable to the difference in the solubility and diffusivity of surfactants at the crack tips.