PURPOSE: We evaluated the diagnostic implications and therapeutic efficacy of antithrombin III(AT III) in the disseminated intravascular coagulation(DIC) of premature infants. METHODS: Ninety-two premature infants diagnosed with DIC and treated with AT III from March, 2000 to May, 2003 were retrospectively reviewed. Clinical manifestations, complete blood counts, coagulation tests, and AT III levels were compared between the two groups:definite DIC if clinical signs of DIC and AT III <70% with more than two abnormal laboratory parameters were present, and suspected DIC if not more than two abnormal laboratory parameters were present. RESULTS: AT III was given for an average of 3.2 days and no side effects related to the treatment were reported. The AT III levels increased significantly more than four fold with treatment in both groups. The clinical signs and laboratory values improved significantly after treatment. CONCLUSION: AT III level is a sensitive parameter in the diagnosis of DIC in premature infants, and it is useful as a treatment modality since it improves the clinical symptoms and the laboratory parameters without significant side effects.