Oxygen consumption (VO2), carbon dioxide production (VCO2), resting metabolic expenditure (RME), RME of that expected for an uninjured resting person of equivalent age, sex, and body surface area (RME%), nitrogen balance, and protein calorie contribution (PCC) were measured in 8 patients with head injury. Metabolic measurements were carried out with the technique of indirect calorimetry from onsets to 14th day. Mean values of VO2 and VCO2 were 298 ml/min, 236 ml/min respectively on admission and those decreased gradually. Mean values of RME%, nitrogen balance, and PCC were 130.6%, -14.5 gm/day, and 17.3% respectively on admission. And those three values significantly decreased on 14th day in those 8 patients. From those facts, it was implied that hypermetabolism and hypercatabolism existed, and measurement of energy expenditure was indispensable to supply enough calorie maintaining body weight and immunocompetence in the acute stage of head injury.