The role of unrelated donor bone marrow transplantation (UD-BMT) in the management of patients with acute myeloid leukaemia (AML) is uncertain. We describe 18 patients with a median age of 13 years (range 4-31) who received an ex vivo T-cell-depleted UD-BMT for AML (13 in second complete remission (CR2) and five in first complete remission (CR1) with high-risk features). Nine donor recipient pairs were fully matched; eight of these donor-recipient pairs had a single class I HLA mismatch; one patient had both single class I and class II HLA mismatches. Grade II GVHD of the skin occurred in four patients (22%) and limited chronic GVHD in two patients (11%). There have been four deaths: one from relapse and three from infection. With a median follow-up of 27 months, 14 patients survive and the actuarial event-free survival at 2 years is 70 +/- 20% (95% confidence interval). We conclude that unrelated donor BMT can result in prolonged disease-free survival in children and young adults with AML.