A diagnosis of AIDS shortly after the detection of HIV antibodies suggests a long-lasting course of the disease without care. The factors associated with a short delay between the initial HIV-1-positive test and the first AIDS-defining event were identified in 1901 patients from 1985 to 2001 in Lyon University hospitals. A total of 576 individuals (30.3%) had an interval of ≤3 months between the detection of HIV infection and AIDS. The factors independently associated with a delay of ≤3 months were: age from 30 to 44 years [odds ratio (OR) 2.5; 95% confidence interval (CI) 1.9–3.2]; age from 45 to 59 years (OR 5.6; 95% CI 3.9–7.8); age ≥60 years (OR 4.5; 95% CI 2.5–8.1), compared to those<30 years old; heterosexuality (OR 2.4; 95% CI 1.6–3.4); injection drug use (OR 2.1; 95% CI 1.5–2.7); and other exposures (OR 2.4; 95% CI 1.6–3.4), compared to homosexual exposure; two opportunistic infections at AIDS (OR 1.8; 95% CI 1.4–2.4) compared to one; and Pneumocystis carinii pneumonia as initial AIDS event (OR 2.6; 95% CI 1.8–3.7), compared to Kaposi's sarcoma. These results provide opportunities to refocus local public health interventions to reduce delayed access to care.