Stem cell transplantation (SCT) may be a treatment option for patients who have been diagnosed with a haemato-oncological condition, such as leukaemia, lymphoma or multiple myeloma. SCT is a complex and challenging treatment. In particular, allogeneic transplant significantly increases the risk of developing infections. This article provides an overview of allogeneic SCT, discusses why infections are a major problem and highlights the role nurses play in preventing and managing established infections in this patient group.