Acute renal failure (ARF) requiring hemodialysis is not common among patients affectedby influenza  We report two unvaccinated adult patients with smoking habit, which were admitted with severe influenzaA H1N1pdm09 that evolved with shock and required mechanical ventilation. Both patients developed progressive renal failure with oliguria/anuria, associated with urinary of inflammatorysediment with proteinuria, microhe-maturia and in one case also with hypocomplementemia, suggesting acute glomerulonephritis. Renal replacement therapy (RRT) was required in both cases. In one patient, who died of late complications, sequencing of the HA1 segment revealed the previously described D222N mutation associated to severe cases. ARF with RRT appears to be an uncommon complication of patients hospitalized for influenzaA H1N1pdm09 and may be secondary to acute glomerulonephritis.