Synovial sarcoma represents 5% to 10% of all soft tissue sarcomas, with an estimated total of 800 new cases annually in the United States. The median age is 30 years; males and females are almost equally affected. About 70% of cases occur in patients more than 20 years old. Young people less than 20 years of age are mainly affected in the second decade of life. The majority of the tumors occur in para-articular structures in the extremities, and most of them are localized at diagnosis. A recent meta-analysis of 219 patients younger than 21 years old treated by the University of Texas M. D. Anderson Cancer Center's Division of Pediatrics, St. Jude Children's Research Hospital, the German Cooperative Group, and Istituto Nazionale dei Tumori, Milan, found that, as in older people, tumor size larger than 5 cm, residual local tumor or metastases at diagnosis, and progressive or recurrent disease all portended a poor outcome. There are currently no randomized studies of therapy for patients with synovial sarcoma, but such are needed to provide answers to the following questions: Is adjuvant chemotherapy useful in preventing recurrence in patients without visible residual disease after apparently complete surgical removal of localized tumor? Should local radiation therapy be given to all patients who have had complete removal of the primary tumor with clear margins at the time of diagnosis?