Postmortem chemical detns. in cerebrospinal fluid and blood from the right and left sides of the heart were performed in a series of 170 human bodies. Biochemical changes during agony and after death are less marked in cerebrospinal fluid than in blood. Postmortem avg. normal values were obtained 1-22 hrs. after death in non-diabetics and subjects with minimal renal disease. Postmortem cerebrospinal glucose values of more than 200 mg. are evidence of diabetes if pancreatitis and intraven. glucose admn. shortly before death are excluded. The simultaneous presence of acetone and of less than 10 volumes of CO2 per 100 ml. of plasma indicate diabetic acidosis which may be accepted as primary cause of death. Glucose values of less than 100 mg. allow us to rule out severe diabetes. Postmortem cerebrospinal urea values of more than 200 mg., if associated with creatinine values of more than 4 mg. and with positive urinary findings are evidence of uremia which may be accepted as a cause of death. Urea values of less than 100 mg. and creatinine values of less than 2.5 mg. with absence of urinary findings permit ruling out fatal renal failure.