Objective Patients with H1N1 virus infection were hospitalized and quarantined, and some of them developed into acute respiratory failure, and were transfered to the medical intensive care unit of Beijing Ditan Hospital, Capital Medical University in Beijing, China. Methods The clinical features and preliminary epidemiologic findings among 30 patients with confirmed H1N1 virus infection who developed into acute respiratory failure for ventilatory support were investigated. Results A total of 30 patients(37.43 ± 18.80 years old) with 2009 influenza A(H1N1) related acute respiratory distress syndrome(ARDS) received treatment with mechanical ventilation, 15 cases of whom were male and 17 cases died of ARDS. Fatal cases were significantly associated with an APACHE Ⅱ score(P = 0.016), but not with PaO 2 /FIO 2(P = 0.912) and chest radiograph(P = 0.333). The most common complication was acute renal failure(n = 9). Five patients received extracorporeal membrane oxygenation(ECMO), 3 of whom died and the others survived. The major causes of death were multiple organ dysfunction syndrome(MODS)(39%), intractable respiratory failure(27%) and sepsis(20%). Conclusions Most patients with respiratory failure due to influenza A(H1N1) virus infection were young, with a high mortality, particularly associated with APACHE Ⅱ score, secondary infection of lung or type 2 diabetes mellitus. Objective Patients with H1N1 virus infection were hospitalized and quarantined, and some of them developed into acute respiratory failure, and were transfered to the medical intensive care unit of Beijing Ditan Hospital, Capital Medical University in Beijing, China. Methods The clinical features and preliminary epidemiologic Results among 30 patients with confirmed H1N1 virus infection who developed into acute respiratory failure for ventilatory support were investigated. Results A total of 30 patients (37.43 ± 18.80 years old) with 2009 influenza A (H1N1) related acute respiratory distress syndrome (ARDS) received Treatment with mechanical ventilation, 15 cases of whom were male and 17 cases died of ARDS. Fatal cases were significantly associated with an APACHE II score (P = 0.016), but not with PaO 2 / FIO 2 (P = 0.912) and chest radiograph (P = 0.333). The most common complication was acute renal failure (n = 9). Five patients received extracorporeal membrane oxygenation (ECMO), 3 of whom The major causes of death were multiple organ dysfunction syndrome (MODS) (39%), intractable respiratory failure (27%) and sepsis (20%). Conclusions Most patients with respiratory failure due to influenza A (H1N1 ) virus infection were young, with a high mortality, particularly associated with APACHE II score, secondary infection of lung or type 2 diabetes mellitus.