Although recipients of unrelated cord blood can tolerate a greater degree of HLA-disparity than recipients of unrelated bone marrow, cell dose is also important. After an unsuccessful search for a bone marrow donor, and after initially dismissing a cord blood search because the patient was 52 kg, we used a different search strategy to identify an unrelated cord blood unit. This led to successful engraftment and transplantation for a patient with no bone marrow donor.