Hypothermia is seen in diabetic acidosis and its features may complicate the evaluation of the diabetic state. These include cardiac arrhythmias, low or normal temperature in the presence of infection, hypotension, depressed sensorium, moderate acidosis and possible resistance to the effects of insulin. Leukopenia may also be a feature of hypothermia in some of these patients. Speculation that hypothermia is dueto an intracellular lack of substrate for the production of heat in a number of diverse states is discussed.