Twenty-four US states have criminal statutes that prohibit HIV-positive persons from engaging in sexual activities without prior disclosure of their HIV status to prospective sex partners. One of the putative goals of these laws is to increase serostatus disclosure by HIV-positive persons, with the expectation that HIV-negative persons will be more likely to take steps to protect themselves from infection if they know their partner has HIV. However, the effectiveness of these laws in encouraging serostatus disclosure, the relationship of disclosure to safer sex practices, and the potential of these laws to inadvertently foster HIV-related stigma or other negative consequences is not known. To begin to address these knowledge gaps, we propose a study with the following specific aims: 1) To determine the extent to which HIV-positive persons living in Michigan are aware of and understand Michigan's criminal HIV disclosure law. 2) To assess the effectiveness of Michigan's criminal HIV disclosure law in reducing HIV transmission risk activities. 3) To determine whether Michigan's criminal HIV disclosure law has any unanticipated negative effects on HIV-positive persons who are knowledgeable about the law such as increasing perceived HIV-related stigma or perceived need to conceal one's disease. To achieve these specific aims we will survey 400 HIV-positive men and women recruited from throughout the state of Michigan. Respondents will be asked to provide information about their familiarity with, sources of information about, and knowledge of Michigan's HIV disclosure law, their recent sexual and disclosure behaviors, and their perception of HIV-related stigma and the need to conceal their HIV status. The findings of this study will be disseminated in academic journals and through conference presentations, and will be summarized in a written report and presentation to policy makers in Michigan.