Two patients with acute myeloid leukemia (AML-M7 and AML-M4) and trisomy 10 as the sole chromosome abnormality are reported. In the first patient, all karyotypes were abnormal. A karyotypically normal cell population was present in the second patient and the trisomic cells were less numerous than the normal ones at diagnosis. A review of the literature shows the rarity of isolated trisomy 10 in hematopoietic disorders and the diversity of the involved diseases. Moreover, in some patients, the trisomic cell population was less numerous than the normal one. These data are discussed in relation with the hypothesis that cells with trisomy 10 can belong to nonmalignant clones, at least in some cases, as previously shown for trisomy 7 in other conditions.