AIDS-defining clinical conditions (also known as AIDS-defining illnesses or AIDS-defining diseases) is the list of diseases published by the Centers for Disease Control and Prevention (CDC) that are associated with AIDS and used worldwide as a guideline for AIDS diagnosis. CDC exclusively uses the term AIDS-defining clinical conditions, but the other terms remain in common use.

This list governs the US government's classification of HIV disease. This is to allow the government to handle epidemic statistics and define who receives US government assistance. However, considerable variation exists in the relative risk of death following different AIDS-defining clinical conditions.^{[further explanation needed]}

According to the CDC definition, a patient has AIDS if they are infected with HIV and have either:^{[citation needed]}

A patient presenting one of the above conditions but with laboratory evidence against HIV infection is not normally considered to have AIDS, but an AIDS diagnosis may be given if the patient has had Pneumocystis jirovecii pneumonia, and has not:^{[citation needed]}

Are the following:^{[citation needed]}

Additional conditions are included for children younger than 13:

In 1993, the CDC added pulmonary tuberculosis, recurrent pneumonia and invasive cervical cancer to the list of clinical conditions in the AIDS surveillance case definition published in 1987 and expanded the AIDS surveillance case definition to include all HIV-infected persons with CD4+ T-lymphocyte counts of fewer than 200 cells/μL or a CD4+ percentage of less than 14. Outside the US, however, diagnosis with a listed opportunistic infection is still required.^{[citation needed]}

It has been suggested that other conditions (such as penicilliosis) should be included in other countries.