In this article, I analyse the construction of risk in AIDS’s clinical medicine on the basis of the arguments and forms of rhetoric at stake in the presentation of the aetiology of the disease, viral transmission and the relationship between organic processes and social processes by a group of professionals engaged in the care of people living with HIV (PVHIV) and interviewed at two times of the epidemic (1993-1994 and 1998-2000). In reconstructing the narrative that links scientific findings, epidemiological evidence, symptoms and signs in patient care, diagnostic classifications, pathogenic presentations, etc., I highlight a set of meaningful movements through metonmical processes linking transmission routes, social behaviour, cause and risk. From that point, the issue of individualisation of the risk in the care of PVHIV, specifying which components or aspects of sexual life, gender relationships, drug use and the lifestyles of those affected play significant roles in clinical operation and make it possible to establish criteria or indicators for defining the individual possibility of contracting or developing the disease and of taking care behaviour in particular in the implementation of antiretroviral treatments. In this article, the construction of risk in AIDS related clinical Medicine is analysed. The arguments and rhetoric in the presentation of the etiology of the illness, viral transmission and the relationship between organic and social processes by a group of medical professionals engaged in the care of persons living with HIV and interviewed during two moments of the epidemic (1993-1994 and 1998-2000) are studied. The paper reconstructs the narrative which reports scientific findings, epidemiological evidence, signs and symptons identified in patient care, diagnostic classifications, pathogenic Presentations, and so on. It further identifies metonymies that link transfer routes, social behaviour, cause and risk. The determination of risk individualisation in medical attention is addressed through the identification of aspects of sexual lives, gender relationships, drug consumption and ways of living of the affected persons that play significant roles in clinical work and contributing to the establishment of the individual possibility of contracting and/or developing AIDS and of adopting care behaviors, especially regarding the application of antiretroviral properties.