Late graft rejection following allogeneic bone marrow transplantation (BMT) for aplastic anaemia is a significant clinical problem and is associated with a high risk of mortality. We report two children with severe aplastic anaemia (SAA) who developed very late graft rejection 2 years and 4 months and 10 years respectively after allogeneic BMT from HLA-identical siblings. Following a second BMT from their initial donors, engraftment has been sustained in both cases. The patients are alive with full donor chimaerism, 18 and 19 years from initial transplant. These cases illustrate that graft failure can be an extremely late event after allogeneic BMT for SAA, and that long-term sustained engraftment can be achieved in these patients with second BMT from the original donors.