RAT pertains to an individual's daily pattern of routine activities, including vocational activities and leisure activities in cyberspace that increase the potential for computer-crime victimization. Also of importance is one of the three major tenets of RAT, "capable guardianship." This pertains to how computer security, as an important capable guardian in cyberspace, plays a major role in countering computer-crime victimization. Overall, the study findings provide empirical support for major theoretical elements in two traditional victimization theories, which entail empirical prediction. From RAT, the researcher hypothesized the degree of installed major computer-security software differentiates the rate of computer-crime victimization. The findings provide support for this proposition by indicating the higher the number of installed computer-security programs with the higher duration, the less the computer crime rate. From lifestyle-exposure theory, the researcher posited three specific propositions. First, the more time online users spend in cyberspace, the greater the likelihood they will be victimized. Second, online users who have higher risky online behaviors are more likely to be victimized. Third, online users who inadequately manage the installed computer-security program will more likely be victimized. Even though the findings offer empirical support for the first and second propositions, the study was unable to make any statistical conclusion on the third proposition, because the computer-security management variable was removed from the model due to its low correlation with other online lifestyle variables; this would distort the statistical findings. In summary, the findings from this study provide an overall picture of the relationships among computer security, online lifestyle, and individual computer-crime victimization. 49 tables, approximately 130 references, a subject index, and appended computer victimization survey