BACKGROUND: Thrombosis involving a brain infarction frequently occurs in patients with a malignant tumor. Although nearly all types of tumor have been reported in association with a hypercoagulable state, pleural mesothelioma-associated Trousseau syndrome is extremely rare. SUMMARY: A 69-year-old female was admitted to our hospital with cough, sputum, and breathing difficulties. She was diagnosed as having a mesothelioma from a percutaneous pleural biopsy. Although there were no risk factors for atherosclerosis, brain infarctions showed frequent relapses, even under anticoagulant therapy, and there was a marked hypercoagulable state. CONCLUSION: Attention should be paid to this syndrome when unexplained brain infarctions occur in patients with pleural mesothelioma.