Metastatic malignant mesothelioma of the pleura is uncommon at the time of initial diagnosis. The gastrointestinal lumen is rarely found at autopsy in patients with widespread disease. Here, we describe an extremely rare case of isolated duodenal metastasis of sarcomatoid mesothelioma of the pleura in a 73-year-old man, without memory of any direct exposure to asbestos. The possibility of gastrointestinal tract metastasis should be considered in the presence of anemia or positive occult blood test in patients with malignant pleural mesothelioma.