This study focused on the utilization of Tarasoff principles with HIV-positive clients when the threat of infection to a third party exists. There are often no clear ethical guidelines to follow when faced with this dilemma, and many clinicians are unaware of what state laws would permit or require them to do. Many variables are important to consider in this complicated area of clinical work, such as the client's level of dangerousness, the client's gender, the clinician's knowledge about HIV transmission risks and endorsement of stigmatizing beliefs. Even with their education and experience, psychologists are not impervious to stigmatization toward HIV-positive persons, which could influence ethical decision-making. Psychologists were presented a vignette describing the sexual behaviors of one hypothetical HIV-positive client. The 6 vignettes were varied by client gender (male, female) and client dangerousness (high, medium, low). Level of client dangerousness was the most significant predictor of likelihood of breaching confidentiality, certainty about decision, and perceptions of client danger. Client gender was not a strong predictor in this model. Stigmatization was not associated with likelihood of breaching confidentiality, but clinicians with high knowledge were significantly more likely to breach than those with low knowledge. Additionally, prior and/or current clinical contact with HIV-positive clients was not associated with likelihood of breaching confidentiality. Overall, the psychologists were knowledgeable about HIV transmission risks and did not endorse stigmatizing beliefs. Implications for future research are also discussed.