The JAK2 V617F mutation is common in patients with Philadelphia-negative chronic myeloproliferative neoplasms, but few cases of the JAK2 V617F mutation have been described in Philadelphia-positive chronic myeloid leukemia (CML) patients. Here, we report a 21-year-old female who presented with phenotype of CML in whom BCR-ABL transcript and JAK2V617F mutation co-occurred. These findings were determined through cytogenetic analysis, fluorescence in situ hybridization, and allele-specific (AS) PCR. The patient's BCR-ABL transcript disappeared after 6 months of treatment with imatinib, while the JAK2V617F mutation remained positive. We discuss this case with reference to the current literature.