Kasabach-Merritt Phenomenon (KMP) is characterized by profound thrombocytopenia, microangiopathic haemolytic anaemia and consumptive coagulopathy in the presence of an enlarging vascular lesion. The syndrome usually develops in infancy and is associated with a high morbidity and mortality rate. We report a case of successful management of refractory KMP in a very small infant with the use of vincristine. A female neonate was born with a giant haemangioma on the right thigh and soon presented with coagulopathy and severe thrombocytopenia due to rapid enlargement of the lesion. The condition proved refractory to steroids and propranolol, and the baby was on supportive therapy with daily administration of red blood cells, platelets and cryoprecipitate. Treatment failure and the risk of serious bleeding led to the decision of starting vincristine on the 45th day of life. During the first week of therapy, haematological parameters improved rapidly, and on the second week, the infant had no need for blood products. By the third week of treatment, platelet count and fibrinogen levels had normalized, and the tumour size was dramatically reduced. The infant completed therapy without experiencing any side-effects and had no relapse during the two years that followed. Vincristine proved to be safe, effective and well tolerated in the treatment of this young baby with severe form of KMP. The report, also, highlights the need for considering vincristine early in the management of KMP, especially in cases of rapidly expanding haemangiomas that raise the suspicion of possible malignant lesions (kaposiform haemangioendothelioma/tufted angiomas).