We present here the case of a 33-year-old Chinese female patient with synchronous double primary malignant tumors (chronic myeloid leukemia [CML] and classic Hodgkin lymphoma). This patient was admitted to our hospital because of bilateral cervical lymph node enlargement and recurrent fever for 2 weeks. The complete blood cell count revealed white blood cell counts of 18.2×109/L, hemoglobin of 9.6 g/dL, and platelet counts of 1,547×109/L. Chromosome karyotype analysis demonstrated that t(9;22)(q34;q11) was positive in all 20 cells examined. Reverse transcription polymerase chain reaction showed that the ratio of BCR/ABL1 to ABL was 45.3%. This patient was diagnosed with CML. After definite diagnosis, this patient regularly received imatinib therapy. Three months later, although complete blood count was normal, swollen lymph nodes further increased. Swollen lymph node biopsy was performed to evaluate the nature of these swollen lymph nodes, and results displayed that Hodgkin and Reed-Sternberg cells, CD30, CD15, and Epstein-Barr virus-encoded RNA was positive. In conclusion, this patient was diagnosed with synchronous double primary malignant tumors. This case report suggests that swollen lymph nodes may be due to lymphoma, rather than as a clinical manifestation of CML.