A dicentric chromosome, dic(16;22), resulting in the loss of 16q and 22p was seen in bone marrow cells from two patients with acute myelomonocytic leukemia and one patient with a therapy-related myelodysplastic syndrome that evolved to leukemia. Review of the clinical findings and of the bone marrow morphology failed to reveal any distinctive features in common among these patients. The dic(16;22) may be a new, rare, recurring abnormality associated with malignant myeloid disorders.