We report the results of unrelated cord blood transplantation (CBT) after myeloablative conditioning in 21 patients over the age of 45 years. Among the patients the median age was 48 years (range, 45-53 years), the median weight was 58.6 kg (range, 43.6-76.2 kg) and the median number of cryopreserved nucleated cells was 2.45 x 10(7)/kg (range, 1.63-3.71 x 10(7)/kg). Nineteen patients had myeloid reconstitution and the median time to more than 0.5 x 10(9)/l absolute neutrophil count was 22 d. A self-sustained platelet count more than 50 x 10(9)/l was achieved in 17 patients at a median time of 49 d. Acute graft-versus-host disease (GVHD) above grade II occurred in 7 of 19 evaluable patients and chronic GVHD occurred in 14 of 16 evaluable patients. Among 14 chronic GVHD patients, in seven patients the disease was extensive. Fifteen patients were alive and free of disease at between 217 and 1798 d after transplantation. With a median follow-up of 847 d, the probability of disease-free survival at 2 years was 71.4%. These results suggest that patients over 45 years of age without suitable related or unrelated bone marrow donors should be considered as candidates for CBT.