Kasabach–Merritt syndrome involves thrombocytopenia, which is usually severe, in association with haemangiomata. We describe two newborn infants who developed life-threatening Kasabach–Merritt syndrome but who were successfully treated. Both had failed to respond adequately to corticosteroids and α-interferon. They subsequently received emergency radiotherapy. Both patients had an improvement in their platelet counts. The first infant’s haemangioma gradually faded during the first 3 years of life, whereas the second infant’s haemangioma had resolved 2 months after radiotherapy. No significant late effects of the radiotherapy have been noted at the 8 and 5 years follow up respectively. Radiotherapy remains an important treatment method in Kasabach–Merritt syndrome when patients fail to respond to other treatments.