Irrespective of the numerous possibilities for avatar selection and customization, research claimed that White avatars compared to avatars from other ethnicities are overrepresented in online environments. The present experiment investigated how existential threats, namely the awareness of one's own mortality (mortality salience, MS) affects the preference for White over Black avatars in a life-simulation game (SIMS III). In addition, the success of a White versus Black avatar as potential influence on avatar-choices was examined.White participants (N = 65) were assigned to a MS versus control condition and watched a game-play video of a human chess game that was won either by the White or by the Black team. Drawing upon terror management theory, we predicted White individuals to prefer in-group to out-group avatars under conditions of MS. We further asked whether the in-game success of the teams would attenuate this in-group bias. The results revealed an increased preference for in-group over out-group avatars under conditions of MS. Success did not affect the pattern. The results are discussed concerning the role of existential anxieties for the behavior in virtual worlds.