Prevention of AIDS is very complex and requires, apart from basic knowledge about modes of transmission and protection, individual awareness of personal risk of infection and modification of one's risky behavior. Perception of risk has been suggested as an important element of sexual behavior change among people who engage in behaviors that place them at risk of HIV infection. This study investigates perceived risk of an HIV infection among inhabitants of municipality of Palilula. The purpose of this study was to determine the relative accuracy of risk assessment, especially for those with high-risk sexual behavior and to assess the factors related to self perception of developing AIDS. The survey was conducted as a household survey in Belgrade municipality "Palilula". The design of the survey was based on a two-stage stratified random sample. The population of Palilula municipality was divided in two stratums and 840 households were selected from each stratum. All members of selected households aged 15-49 years were interviewed. Total of 2659 persons was interviewed. Self administered questionnaire, developed by WHO and described in the Evaluation of National AIDS Programme: A Methods Package 1. Prevention of HIV infection, Geneva, 1994, was translated and adapted for local application. For analysis of findings methods of descriptive statistics, chi square test and logistic regression were used. Statistical analysis was performed using SPSS/PC. The results showed that most of the respondents (1662, 62.5%) do not perceive themselves to be at risk of HIV infection. Interestingly, almost one quarter of the sample couldn't estimate personal chances of being HIV infected. Significantly larger proportion of respondents living in urban area than those living in rural area perceived themselves at risk (17.1% of urban vs. 7.7% from rural area, chi square = 54.06, Ir0.00). Significant differences between age groups were found for perception of personal risk. Respondents up to 19 and those older than 25 in more than 60 percent and only a half of those between 20 and 24 believed that there was no chance they could become HIV infected. Almost 16% of respondents between 20 and 24 believed that they had some chances of contracting HIV, also approximately one third of them couldn't estimate personal risk of contracting HIV infection (chi square = 2.10, p = 0.00)(Graphe 1). Those who engaged in sex with irregular partners were found to perceive themselves in higher risk then those who were engaged in sex only with regular partners in previous 12 months. One fifth of those with irregular partners estimated their chances as good versus only 10% of those with only regular partners. A logistic regression analysis found that those who believed they were personally at risk knew someone with HIV, had more irregular sexual partners in last 12 months, were younger, and lived in urban area (Table 1). People correctly perceived the risk of HIV infection as being minimal as most of them didn't engage in risk behavior. Risk perception was higher among those who had more irregular partners, younger and those from urban area. Most important predictor of risk perception was knowledge of HIV positive individual.