The present case report describes a gastric cancer which showed unusual metastasis in the oral region. A 56-year-old male patient underwent total gastrectomy and splenectomy due to advanced gastric cancer in the upper third of the stomach. Fifteen months later, he presented with anorexia and gingival swelling of durations of approximately 3 and 1 month, respectively. The gastric tumor was histologically a signet ring cell and a poorly differentiated cancer with a moderate degree of vascular invasion. Biopsy specimens from the gingival tumor revealed a signet ring cell cancer. Other metastatic sites were the brain, limb bones and abdominal lymph nodes. A bone scintigram revealed an abnormal uptake in the limb bones, while it did not exhibit any abnormality in the oral region. Correlation between the histology of the gingival tumor with that of the gastric cancer, as well as the absence of a gingival tumor at the time of prior gastrectomy, led to a diagnosis that the gingival tumor was a metastasis from gastric cancer. Gastric cancer metastasizing to the oral region, either the osseus or the oral soft tissue, is very rare. Although it cannot be proved without an autopsy, negative findings in the mandible by bone scanning in the present case suggest that direct gingival metastasis can be considered, rather than mandibular metastasis involving the gingiva. Hematogenous spread could be a mechanism of metastasis for this unusual tumor.