Purpose: Kasabach-Merritt syndrome (KMS) is a rare, but life-threatening illness which often leads to serious bleeding complications. The purpose of this study is to report our single center experience with KMS. Methods: We reviewed the medical records of 13 patients who were diagnosed as KMS from 1997 to 2012 at out institution. Response to treatment was defined as follows: 1) hematologic complete response (HCR) – platelet count above 130 x 10sup＞9/sup＞/L without transfusional support; 2) clinical complete response (CCR) – complete disappearance or small residual vascular tumor not proliferating for at least 6 months after discontinuing any type of medical treatment. Results: Seven males and 6 females were identified and their median age at diagnosis was 30 days (range, 0-593). Diagnosis was made with typical clinical and radiologic findings except for one patient whose mass was biopsied at initial presentation. The median values of initial Hb and platelet count were 9.7 g/dL (range, 6.6-11.6) and 11 x 10sup＞9/sup＞/L (range, 3-38), respectively. The most frequent locations were extremities (n=7) followed by trunk (n=2), retroperitoneum (n=2), neck (n=1), and spleen (n=1). Twelve patients received steroid and interferon-α as an initial treatment modality with the other one receiving propranolol instead of steroid along with interferon-α. Two patients who showed relative resistance to initial treatment received weekly vincristine. One patient was lost to follow-up at 12 mo from diagnosis not achieving HCR or CCR. Among the other 12 patients, medications could be successfully discontinued in all but one patient who is currently maintained with propranolol having small residual retroperitoneal tumor with normal platelet count. The median times to achieve HCR and CCR were 157 days and 332 days, respectively. It took a median of 301 days (range, 137-579+) before discontinuing all medical treatment. The probabilities to attain HCR and CCR at 1 y were 77% and 54%, respectively, and they increased to 88% and 86% at 2.5 y, respectively. Conclusions: The prognosis of KMS in our cohort was excellent. Although the rate of response was variable, most cases eventually responded to prolonged treatments. Our data suggest that individualized treatment adaptation according to response may be very important to successfully treat patients with KMS.