We describe a case with the simultaneous occurrence of chronic myelogenous leukemia (CML) and non-Hodgkin lymphoma (NHL). Peripheral blood (PB) and bone marrow (BM) smears showed typical CML features. Lymph node biopsy exhibited a large-cell NHL. The Philadelphia chromosome or its molecular counterpart, the BCR-ABL gene fusion, by detecting with dual color-(DC) fluorescence in situ hybridization (FISH), was detected reliably both in metaphase spreads from BM and in interphase nuclei from BM and follow-up PB cells, but was not detected in the lymph node cells. Clinical features and laboratory findings show this case having a coexistence of CML and NHL.