Synovial sarcoma is a malignant soft-tissue tumor that most commonly occurs in the extremities of young adults. Only several cases of synovial sarcomas of the chest wall and pleura had been reported. We present a 24-year-old man who had right back pain, chest pain, dyspnea, and intermittent fever from a huge primary synovial sarcoma of the right posterior chest wall. Multimodality therapies, including surgical resection, and chemotherapy and radiation therapy were applied, but the tumor progressed rapidly and the patient died 6 months after diagnosis. Prompt diagnosis and aggressive surgical resection is mandatory for primary synovial sarcoma of the chest wall because of its aggressive behavior.