Imatinib mesylate is the standard treatment of chronic myeloid leukemia (CML). Despite imatinib is being used in the treatment of other malignancies as well, its potential role on de novo tumor growth is not known. Secondary malignancies are rarely seen in patients with CML and particularly in those receiving imatinib. Here, we present a CML patient taking imatinib therapy that was diagnosed to have breast cancer and received adjuvant chemo-and radiotherapy with imatinib. We tried to explain co-occurrence of these rare events by probable pathogenetic mechanisms.