Spontaneous remission of acute myeloid leukemia (AML) in adults is a rare but well documented phenomenon. This study reports on a 64-year-old male patient with acute myelogenous leukemia (AML-M4, according to the French-American-British classification) that was developed on a background of chronic myelomonocytic leukemia (CMML) and then underwent remission after treatment with the gonadotropin-releasing hormone agonist (GnRH agonist) triptorelin for presumed prostate cancer. Remission persisted for at least 4 years before the patient was lost to follow-up. To the author' knowledge, this is the first report of remission in an AML-M4 case associated with hormone manipulation. Possible mechanisms of this phenomenon are discussed.