The present study examined association between anonymity and antisocial individual behavior without any influence from the presence of others. Anonymity was operationally defined as consisting of two components, nonidentifiability and nonaccountability. Antisocial behavior was defined as rule-breaking behavior seeking a monetary reward. It was hypothesized that anonymity would increase antisocial behavior among individuals. Undergraduate students (20 men, 50 women) were recruited from two psychology classes and were randomly assigned to four experimental conditions (Anonymous, Nonidentifiable, Nonaccountable, and Nonanonymous) to examine whether they would violate game rules to obtain the monetary reward through anonymity. Only participants in the Anonymous condition violated the rules to obtain the reward. Implications for the effects of anonymity on antisocial individual behavior are discussed.