Objective: To measure the frequency of late-stage HIV diagnoses among patients in the Dat'AIDS cohort in the French West Indies (Martinique and Guadeloupe) and to describe their characteristics and clinical and biological outcomes in comparison with patients diagnosed at the same stage in mainland France (16 centers). Methods: Data were extracted for patients in the Dat'AIDS cohort whose diagnosis date fell between January 1, 2014, and December 31, 2015. Patients were classified as "Antilles" or "metropolitan France" based on the center where they received care following their first positive screening test. Baseline demographic variables, screening conditions, and clinical and biological progression in the two groups were compared at 6 and 12 months post-diagnosis. Diagnosis at an advanced stage was defined as a CD4 count <200/mm³ at the time of diagnosis or AIDS within the following three months. Results: The analyses included 2,597 patients, of whom 254 were diagnosed in the Antilles. Diagnosis at an advanced stage occurred in 36.6% of patients in the Antilles and 28.8% of patients in mainland France (p=0.009). The time to initiation of treatment was longer in the French West Indies than in mainland France: median 34 days (IQR 20–49) vs. 24 days (IQR 14–44), p=0.002. The proportion of patients with a viral load <50 copies/mL at 6 months was 75.7%, with no difference between the two groups. Conclusion: The frequency of diagnosis at an advanced stage of HIV infection was higher in the French West Indies than in mainland France. The clinical and virological course of patients diagnosed at an advanced stage did not differ between the two regions.