Post-transplant lymphoproliferative disorders (PTLD) are a well recognised complication of conventional haemopoietic stem cell transplantation (HSCT). Reduced intensity HSCT involves intensive immunosuppression to permit engraftment. Thirty reduced intensity transplants with the FBC (fludarabine 150 mg/m2, busulphan 8 mg/m2, CAMPATH-1H 100 mg) protocol have been performed at our centre, with one confirmed EBV-positive PTLD. The female recipient developed a perforated viscus day +191 following HSCT from a volunteer unrelated male donor. A large caecal mass and a retroperitoneal abscess were excised, revealing an EBV-positive diffuse large B cell lymphoma confirmed by FISH to be of donor origin. More experience is required before the risk of PTLD in this setting can be assessed.