Two experiments investigated if and how visual representation of interactants affects depersonalization and conformity to group norms in anonymous computer-mediated communication (CMC). In Experiment 1, a 2 (intergroup versus interpersonal) × 2 (same character versus different character) between-subjects design experiment (N= 60), each participant made a decision about social dilemmas after seeing two other (ostensible) participants’ unanimous opinions and then exchanged supporting arguments. Consistent with the Social Identity model of Deindividuation Effects (SIDE), when the group level of self-identity was rendered salient in an intergroup encounter, uniform virtual appearance of CMC partners triggered depersonalization and subsequent conformity behavior. By contrast, when the personal dimension of the self was salient, standardized representation tended to reduce conformity. To elucidate the mediation process, Experiment 2 investigated the causal links between depersonalization, group identification, and conformity. The results show that depersonalization accentuated adherence to group norms, both directly and indirectly via group identification.