A 67-year-old woman with metastatic carcinoid tumor developed neurologic signs and symptoms of left facial paralysis and progressive lower extremity weakness. Results of cytologic evaluation of cerebrospinal fluid were normal. However, biochemical analysis of the cerebrospinal fluid showed extreme elevations of 5-hydroxyindoleacetic acid and serotonin, consistent with carcinomatous meningitis caused by carcinoid tumor. Subsequent contrast myelography confirmed the presence of meningeal metastases.