Gastroesophageal adenocarcinoma is a malignant type of cancer, which can metastasize to multiple organs. However, there have not been many case reports in the literature pertaining the relationship of gastroesophageal adenocarcinoma and carcinomatous meningitis. In this case, a 65-year-old African American male with a history of dysphagia was initially diagnosed with adenocarcinoma at gastroesophageal junction. The patient was treated with both chemotherapy and radiation, but chemotherapy was interrupted due to significant weight loss, anemia, and sudden onset of change in mental status. Patient was admitted to our facility for further evaluation of his neurological symptoms. The patient became more confused and delirious during hospital stay, and symptoms could not be explained by radiological studies and laboratory values. Therefore, a lumbar puncture was done to search for infectious and neoplastic causes that were not shown up on Computed Tomography scan (CT) and Magnetic Resonance Imaging scan (MRI) of the brain. The cerebrospinal fluid (CSF) cytology showed metastatic poorly differentiated adenocarcinoma. The patient's prognosis was poor because there is no specific treatment recommendation for primary gastroesophageal cancer at this stage. The patient passed away 4 weeks later under hospice care. The goal of our case report is to raise awareness of the rare metastatic possibility in advanced stage of gastroesophageal adenocarcinoma. In doing so, physicians can help educate and prepare family for unfavorable outcomes.