The effects of low doses of cytosine-arabinoside (Ara-C) were studied in 17 patients with chronic myeloid leukemia: chronic, resistant to IFN and hydroxyurea therapy (including 4 cases of advanced chronic disease)--7, and tumor progression--10. Hematologic effect was recorded in 7 chronic patients tolerant to hydroxyurea and alpha-interferon therapy. Among 10 cases of tumor progression, chronic stage II was observed in 3, stabilization (tumor progression short of blastic crisis)--5, and without effect--1. Low-dose Ara-C treatment was considered effective in 15 (88%) out of 17 patients.