One of the most pervasive stigmatising conditions in society today is HIV/AIDS. In Trinidad and Tobago, stigma and discrimination are still pervasive especially against persons living with HIV/AIDS (PLHIV) and at-risk groups. HIV stigmatisation takes place at all levels including health care institutions, and is a major obstacle to effective HIV/AIDS prevention and care. This study examined health care students' reactions towards HIV patients. A stratified random sample of 339 health care students from Trinidad was used. A 2 × 2 factorial design using vignettes manipulated a male patient's sexual orientation (heterosexual/homosexual) and HIV onset controllability (high/low). Multivariate analysis of variance and discriminant function analysis were used to analyse the data. There was a significant main effect of HIV onset controllability on participants' attribution of blame, emotions, prejudicial evaluation and willingness to interact with PLHIV, Λ (.64) F(6, 330) = 31.44, p <.001, [Formula: see text] = .37. Attribution of blame and prejudicial evaluation discriminated between reactions to patients in low onset control and high onset control vignettes. Cognitive-affective appraisal processes are instrumental in determining health care providers' reaction towards PLHIV.