Spontaneous remission of acute myeloid leukaemia (AML) is extremely rare and usually of short duration. We report two patients with documented AML who developed spontaneous remission of their leukaemia shortly after an episode of severe sepsis and respiratory failure requiring mechanical ventilation. The underlying mechanisms of spontaneous remission remain unclear but an association with preceding blood transfusions and severe systemic infections has been reported. An overwhelming immune response due to sepsis and leading to raised levels of TNF-alpha, INF-gamma, IL -2 and an increased activity of NK cells, cytotoxic T-cells and macrophages are thought to play an important role. Better insights into the mechanisms of spontaneous remission of AML after recovery from sepsis could help in developing new therapies for AML.