Hodgkin lymphoma (HL) is a lymphoproliferative disease arising in the lymphoid tissue, which is characterized by Reed-Sternberg cells. Adenocarcinoma is the most frequent pathological type of stomach cancer. Improved survival in HL patients leads to the development of secondary malignancies. However, synchronous occurrence of these 2 malignancies is extremely rare. Here, we present a 45-year-old male complaining of a lymph node mass in the neck, without any abdominal symptoms, diagnosed as HL and gastric adenocarcinoma with hepatitis B carrier status. We treated the patient with 8 courses of pirarubicin bleomycin, vincristine, and dacarbazine (modified ABVD), and 4 courses of capecitabine therapy concurrently along with oral entecavir, as the patient survived longer than 20 months.The prognosis of multiple primary malignancies is poor because therapy is difficult, without a standard treatment. The frequency of multiple primary malignancies is increasing in recent years, and second malignancies in patients with cancer should be taken into consideration.