Leptomeningeal carcinomatosis (LMC) from gastrointestinal cancer would be rare. A 56-years old man with complaint of dyspepsia and histopathologic examination of the biopsy specimens has shown: adenocarcinoma. At the end of adjuvant chemo radiation therapy, the patient has affected by headache and mild confusion. In cerebrospinal fluid (CSF) cytology, a plenty of malignant cells have seen and unfortunately after a short time for about 4 days after ICU admission, the patient has died. This could be due to heavy burden of disease in central nervous system.