Chronic myeloid leukemia (CML) is a neoplasia characterized by proliferation of a myeloid cell lineage and chromosome translocation t(9;22) (q34;q11.2). As in the case of most cancers, the average telomere length in CML cells is shorter than that in normal blood cells. However, there are currently no data available concerning specific individual telomere length in CML. Here, we studied telomere length on each chromosome arm of CML cells. In situ hybridization with peptide nucleic acid probes was performed on CML cells in metaphase. The fluorescence intensity of each specific telomere was converted into kilobases according to the telomere restriction fragment results for each sample. We found differences in telomere length between short arm ends and long arm ends. We observed recurrent telomere length changes as well as telomere length maintenance and elongation in some individual telomeres. We propose a possible involvement of individual telomere length changes to some chromosomal abnormalities in CML. We suggest that individual telomere length maintenance is chromosome arm-specific associated with leukemia cells.