OBJECTIVE We aim to evaluate the incidence and outcome of acute kidney injury (AKI) among critically ill adult patients with H1N1 2009 infection. METHODS From a prospectively collected influenza A (H1N1) 2009 bi-national, we identified 671 adult patients admitted to intensive care unit (ICU) from June 1 to August 31, 2009. Of these, 628 (93.6%) had admission and/or peak serum creatinine values during ICU stay. We defined AKI according to the creatinine criteria of the RIFLE classification. RESULTS Of 628 adult patients, 211 [33.6%, 95% confidence interval (CI) 29.8-37.4%] had AKI: 41 (6.5%) risk, 56 (8.9%) injury and 114 (18.2%) failure. Of all 211 AKI patients, 76 [36.0% (29.4-42.6%)] died in hospital (36.6% in risk, 25.0% in injury and 41.3% in failure group) compared with 33 of 408 (8.1%) patients without AKI. Among the 33 AKI patients treated with renal replacement therapy, 13 died (39.4%). Mechanical ventilation [odds ratio (OR) 3.62 (2.07-6.34)], any severe co-morbidity (OR 2.36, 95% CI 1.15-3.71), age (OR 1.02, 95% CI 1.01-1.03 per 1 year increase), and AKI (OR 6.69, 95% CI 4.25-10.55) were independently associated with hospital mortality. CONCLUSIONS Acute kidney injury appears common in H1N1 2009 infected patients and is independently associated with an increased risk of hospital mortality.