Antiretroviral therapy suppresses viral replication, increases CD4+ cell-count, decreases AIDS- related mortality and morbidity and comorbidities, improves the quality of life of HIV-infected patients, and prevents sexual transmission of HIV. However, this treatment is unable to eradicate HIV infection. The aims of antiretroviral therapy are reviewed in this article, updating information on when to initiate treatment, which combinations of drugs should be used, what is the best antiretroviral treatment in the presence of AIDS-defining opportunistic diseases, and what clinical parameters should be included in the pre-treatment study and in the patient follow-up. Changes in antiretroviral therapy induced by virological failure or therapy simplification, and how to deal with specific situations such as chronic liver disease or pregnancy are also discussed.