Appropriately aggressive treatment of haematological malignancies can be complicated by a variety of life threatening events. Usually such acute events are, at least theoretically, potentially reversible and in view of the much improved prognosis of the underlying malignancy it is now generally considered to be appropriate to offer intensive care to selected cases, provided there is a reasonable prospect of cure or at least worthwhile palliation. A few remain concerned, however, and question whether the provision of intensive care for such patients is worthwhile. Hospital mortality rates of between 69-80% have been reported for patients admitted to intensive care with medical complications of haematological malignancy and this rises to 80-90% in those with respiratory failure. Overall mortality rates are generally even higher (87-95%) in those who have received a bone marrow transplant (BMT). The median duration of survival following discharge from hospital is in the region of 12-23 months, but a few survive much longer, a number must be presumed cured and their quality of life is good. These disappointing short- and long-term survival rates are achieved at considerable cost and, as is the case in many other categories of critically ill patients, expense and utilisation of resources is much higher in non-survivors than in survivors. Factors associated with a poor short-term outcome include the need for mechanical ventilation, hypotension, the administration of inotropes or vasopressors, an increasing number of failed organs, relapsed or unresponsive malignancy and persistent neutropenia. A poor prognosis may also be associated with increasing age, time on the ventilator and time in intensive care. BMT recipients have a particularly poor prognosis, especially when they require mechanical ventilation, and survival is unprecedented when ventilated BMT recipients either receive vasopressors or develop hepatic and renal insufficiency. It has not been possible to identify any features of the acute illness which influence the duration of long-term survival: this seems to depend solely on the progress of the underlying malignancy, something which is often difficult to predict before or during intensive care. In our view patients with life threatening complications of haematological malignancy should be offered intensive care unless or until it is clear that there is no prospect of recovery from the acute illness or that the underlying malignancy cannot be controlled.