This article provides a description of the most common initial AIDS-defining conditions between 2003 and 2010, based on mandatory AIDS reporting. The number of AIDS cases has stabilized at around 1,500 cases per year since 2007, due to the significant proportion of people who only discover their HIV status at the time of an AIDS diagnosis and who were unable to receive appropriate care (6 out of 10 people in 2010). The median time between discovering HIV status and the onset of AIDS is nearly twice as short among people who did not receive treatment compared to those who did (5.9 and 10.2 years, respectively). The most common initial AIDS-defining illness is now pulmonary Pneumocystis pneumonia, following an increase in the number of cases since 2007. The other initial AIDS-defining illnesses are, in descending order of frequency: tuberculosis, cerebral toxoplasmosis, esophageal candidiasis, Kaposi’s sarcoma, and non-Hodgkin lymphomas. All of these conditions have declined since 2003, particularly tuberculosis, in line with the decrease in the number of AIDS cases among people born abroad. Although these data on people developing AIDS represent only a very specific subsample of the HIV-positive population, they once again demonstrate the importance of early screening. (R.A.)