Objectives. - To describe the characteristics of severe cases of influenza A(H1N1)/2009 at Saint-Pierre Hospital in Réunion during the 2009 epidemic, as well as the measures implemented to address them. Patients and methods. - A prospective observational study including all probable and confirmed cases of influenza A(H1N1) among patients hospitalized in our intensive care unit. For each patient, we collected the medical history, demographic data, treatments initiated, comorbidities, clinical characteristics, severity scores, laboratory results, and chest X-ray findings at admission, as well as treatments received and any complications. We detailed the reorganization of care implemented during this period. Results.—Thirteen patients were included between August and September 2009. Three (23%) had no prior medical history. The median age was 42 years [22–69]. Eleven required mechanical ventilation for 10.3 days (+/- 8). Three (23%) developed ARDS. Three patients (23%) died. The organization of care had to be completely rethought during the epidemic to cope with the influx of cases in our context of geographical isolation: creation of a specific triage pathway, division of the department into sectors, opening of beds, establishment of an on-call system, and inter- and intra-hospital cooperation. Conclusion.- The island of Réunion served as an experimental laboratory for crisis management during the 2009 H1N1 epidemic, several months before mainland France. We believe it is necessary to anticipate the reorganization of care during an epidemic in intensive care units, especially in smaller or more isolated facilities like ours, in order to cope more calmly with a sudden influx of patients. (R.A.)