Primitive neuroectodermal tumors (PNET) belong to the group of small round cell tumors and are rarely seen. They are rapidly progressive tumors, despite usually being treated by a multimodal therapy which includes surgery and chemoradiotherapy. We present two patients with PNET of the thorax treated in our clinic. The first patient had a huge tumor in the right hemithorax, which shifted the mediastinum to the contralateral hemithorax. Diagnosis was established by transthoracic fine-needle aspiration biopsy and the tumor was treated by surgical resection. Surgery resulted in a microscopically incomplete resection. Chemoradiotherapy was given postoperatively. The patient had local recurrence after seven months and died of cranial metastasis. The second patient had a small tumor on the right costovertebral angle which protruded towards the skin and was diagnosed by incisional biopsy. The tumor responded very well to preoperative chemotherapy and complete resection was achieved surgically. Postoperative chemoradiotherapy was also given. This patient had bone metastasis, local recurrence and pleural pulmonary metastasis after 6, 18 and 28 months, respectively, and died 30 months after the operation.We discuss the limited effect of surgery on the treatment of thoracic PNET on the basis of the results of these patients in whom we performed surgery.