A 63-year-old patient with acute myeloid leukemia of FAB M5 subtype revealing chromosomal breakpoints in 3q21 and 3q26 is presented. Although rearrangements of 3q21 and 3q26 are relatively common in patients with myelocytic malignancies, this is the first report of ins(17;3)(q11.2;q21q26.3). We defined the chromosomal breakpoints and the extent of the insertion by fluorescence in situ hybridization (FISH) with yeast artificial chromosomes (YACs).