Abnormal coagulatioin is a frequent complication in patients with head injury. Hemostasis in 56 patients with head injuries, not associated with serious systemic injuries, was screened using platelt count, bleeding time, prothombin time, thrombin time, activated partial thrombin time, fibrinogen level, fibrin degradation product(FDP), protamin sulfate test, ethanol gelation test, and d-dimer test. Frequency of coagulopathy was 28.6% in all patients, 24.2% in the group of Glasgow Coma Scale(GCS) 9~15, and 36.8% in GCS 3~8. Patients with poor outcome, who had Glasgow Outcome Scale(GOS) 1~3, had higher frequency of abnormal laboratory results. Particularly, platelet was significantly reduced in the group of GOS 1~3 than GOS 4~5. In the patients without intracranial hematoma, fequency of coagulopathy was significantly higher in the patients with poor outcome than favorable outcome. In the group of GCS 3~8, patients with hematoma had significantly higher frequency of coagulopathy than patients without hematoma. Coagulopathy did not significantly changed the outcome of the patients. Most of the results of the tests except platelet count FDP returned to normal limit on the follow-up tests done 3 days later.