Trousseau syndrome is characterized by cancer-associated systemic thrombosis. We describe the first case of a successfully treated gallbladder adenocarcinoma accompanied by Trousseau syndrome. A 66-year-old woman presented with right hemiplegia. Magnetic resonance imaging identified multiple cerebral infarctions. Her serum carbohydrate antigen 19-9 and D-dimer levels were markedly elevated, and a gallbladder tumor was detected via abdominal computed tomography. Venous ultrasonography of the lower limbs revealed a deep venous thrombus in the right peroneal vein. These findings suggested that the brain infarctions were likely caused by Trousseau syndrome associated with her gallbladder cancer. Radical resection of the gallbladder tumor was performed. The resected gallbladder was filled with mucus and was pathologically diagnosed as an adenocarcinoma. Her postoperative course was uneventful, and she received a one-year course of adjuvant therapy with oral S-1. No cancer recurrence or thrombosis was noted 26 months postoperatively. Despite concurrent Trousseau syndrome, a radical cure of the primary tumor and thrombosis could be achieved with the appropriate treatment.