This paper aims to: 1/ describe IDU's and non-IDU's according to age, gender, AIDS criteria and antiretroviral therapy; and 2/ assess survival differences between IDU's and non-IDU's according to age, gender, AIDS diagnosis criteria and antiretroviral therapy. This study is a survival study of a longitudinal cohort. The sample was composed of 1,258 AIDS patients of a cohort of HIV-infected adults who sought medical care at either the Immunology clinic of Bayamon or the Ramon Ruiz Arnau University Hospital between 1992 and 1999. The variables studied were: survival time of AIDS, intravenous drug use, age, gender, AIDS defining criteria and antiretroviral therapy (yes/no). The results have been that IDU's had lower survival than non-IDU's. Significant differences in the survival functions (IDU's vs non-IDU's) were found among male patients, older patients, patients with immunological criteria and patients with antiretroviral therapy. The survival among these variables was lower in IDU's than non-IDU's. This study suggested that decreased survival of IDU's may be related to later diagnosis and decreased access to drug therapy. Clinical endeavors should take into consideration the variables related to IDU's survival to develop health programs in order to enhance the quality of life and the survival of the AIDS patients.