Donor lymphocyte infusions were given to 13 consecutive chronic myeloid leukemia patients in relapse after allogeneic stem cell transplantation. Of the 13 patients, 11 achieved a molecular remission and 2 a cytogenetic remission. The median time (range) in months to achieve a hematologic, cytogenetic and molecular remission was 2 (1-2), 5 (1-42) and 5 the median response duration is 16 months (range 1-36), and no patient shows evidence of relapse.