Although gynecomastia is a well-defined paraneoplastic syndrome in patients with non-small cell lung cancer, the association with pleomorphic carcinoma has not been reported. A 50-yr-old man presented with bilateral gynecomastia and elevated serum beta-human chorionic gonadotropin (beta hCG) level. Chest tomography showed a mass in the right middle lobe. Right middle lobectomy and mediastinal lymph node dissection were performed. beta hCG levels decreased rapidly after surgery. Histological examination revealed pleomorphic carcinoma with positive immunostaining for beta hCG. Serum beta hCG levels began to increase gradually on postoperatively 4th month. Computed tomography detected recurrence and chemotherapy was started. After second cycle of chemotherapy, beta hCG levels decreased dramatically again and tomography showed regression in mass. Patient died 6 months later due to brain metastasis. beta hCG expression may be associated with aggressive clinical course and increased risk of recurrence, also beta hCG levels may be used to evaluate therapy response in patients with pleomorphic carcinoma.