Sarcoidosis is a multisystemic inflammatory disease that commonly affects the lungs and lymphatic system and is characterized by the formation of non-caseating granulomas. Although the association between sarcoidosis and malignant diseases has been well described, it remains controversial whether this association is merely a coincidence or the consequence of a common pathophysiological mechanism. The present study reports a rare case of sarcoidosis that was present in a patient with gastric cancer at the time of diagnosis. A 64-year-old female diagnosed with stage I gastric cancer underwent curative surgery, and the postoperative pathology of the lymph nodes revealed non-caseating granulomas. At the 4-year follow-up, the sarcoidosis remained stable, and no recurrence of cancer was identified. The present case revealed that sarcoidosis and gastric cancer may coexist simultaneously and focused on the potential advantages of histological confirmation in patients with cancer and sarcoidosis.