For oral metastases, the most common primary sites are lung and prostate among male patients and breast among females, but oral metastasis from rectal adenocarcinoma is extremely uncommon in both genders. Tumors tend to metastasize to jaw bones more often than to oral soft tissues. In case of oral soft tissue metastases, the gingiva and the tongue are the most commonly involved sites. The prognosis of patients with oral metastases is poor; but early detection and effective treatment are necessary to avoid patient discomfort, secondary infection and subsequent tissue destruction.Here we report a case of rectal adenocarcinoma that metastasized to the oral mucosa of the lower buccal sulcus. Pain and discomfort during chewing were the main complaints. In this case report, the histopathological findings, the management of the oral metastasis, and patient prognosis are discussed.