BACKGROUND: An early diagnosis of disseminated intravascular coagulation (DIC) before its progression to an overt stage is necessary for early treatment and positive outcomes. In 2001, the Scientific and Standardization Committee (SCC) of the International Society on Thrombosis and Hemostasis (ISTH) proposed new criteria for the preclinical diagnosis of overt and non-overt DICs. We investigated the clinical usefulness of the modified ISTH criteria for non-overt DIC diagnosis. METHODS: We enrolled 296 DIC patients (170 males and 126 females) admitted and evaluated at the Gangnam Severance Hospital, Seoul, Korea, between March 2006 and April 2007. Hemostatic tests, including platelet counts, prothrombin time (PT), D-dimer levels with antithrombin, and protein-C levels, were evaluated by excluding negative scores with clinical signs, in which more than 5 points of interest denoted non-overt DIC. Mortality rates were also evaluated. RESULTS: There were 289 patients with increased D-dimer levels and significant parametric changes suggesting DIC progression. Protein C and antithrombin levels were lower (99.2% each) and appeared earlier in patients with non-overt DIC than in patients with overt DIC. In all, 125 (43.3%) patients had non-overt DIC and, of which 27 died (mortality rate, 21.6%). The sensitivity and specificity for mortality were 73.0% and 55.9%, respectively, which were same as those for the original ISTH criteria. CONCLUSION: The modified ISTH criteria can be used for the early detection of non-overt DIC, and may be useful for the improvement of outcomes of non-overt DIC patients.