Risk factors for delayed HIV diagnosis in French Guiana were studied in 1952 patients between 1992 and 2003. At the time of diagnosis, 30% of patients had less than 200 CD4 lymphocytes/mm3; age, male sex, and foreign nationality were independently associated with a low CD4 cell count. The availability of highly active antiretroviral therapy was not associated with an earlier HIV diagnosis. Promoting HIV information and testing should be done in several languages to reach minorities.