OUTLINE: Patients receive azacytidine subcutaneously on days 1-7 and phenylbutyrate IV over 1-2 hours on days 8-12. Patients with acute myeloid leukemia who respond to therapy may receive a second course approximately 10 days after the end of the first. Subsequent courses in these patients, and all additional courses in all other patients, are repeated every 21 to 28 days in the absence of disease progression or unacceptable toxicity.