Hepatic sinusoidal obstructive syndrome (HSOS) is a frequent complication in patients undergoing haematopoietic stem cell transplant (HSCT), and more rarely, in paediatric patients receiving conventional chemotherapy for solid tumours. Its diagnosis relies on a combination of clinical signs and symptoms such as hepatomegaly, jaundice, weight gain and fluid retention. HSOS treatment is primarily based on supportive care and anti-fibrinolytic agents. Here we report two patients affected by Wilms tumour who developed life-threatening HSOS that failed to respond to conventional treatment. Both patients recovered after receiving aggressive supportive treatment that included administration of non-activated protein C (Ceprotin®—Baxter). Pediatr Blood Cancer 2014;61:940–941. © 2013 Wiley Periodicals, Inc.