The most important factors in determining the outcomes of patients with traumatic brain injury (TBI) is the degree of severity and types of primary brain damage, and the secondary damage to the brain such as low-oxygen and low-blood pressure et al. For severe TBI patients, prompt and appropriate decompression to reduce intracranial pressure (ICP) and ICU management are commonly required. The second edition of "Guidelines for the Management of Severe Head Injury" was published by the Japan Society of Neurotraumatology (JSNT) in 2006. These guidelines include a wide range of topics in the management for severe TBI, from prehospital care, primary care, ICU management and surgical treatment. The essence of extended decompression and neuroprotection for TBI is also focused in the JNST Guidelines. The pathophysiological event in the acute stage of severe TBI is quite variable ; therefore, an appropriate individual based approach in ICU management is necessary under experienced medical teams.