Objective To analyze the radiological and clinicopathological features of synovial sarcoma (SS) to improve its diagnostic accuracy. Methods We retrospectively reviewed the computed tomography (CT) and magnetic resonance (MR) imaging of 15 cases of SS confirmed immunohistochemically. Relevant clinical data was also obtained. Results Of 15 cases, there were 7 male and 8 female with a mean age of 42 years(range 17–65 years). The main symptoms were the aggravated pain of the lesion site and enlarged palpable masses. The duration of symptoms varied from 7 days to 2 years with a mean of 4.7 months. Fifteen lesions were located in the thigh (n=5), crus (n=3), foot(n=1), retroperitoneum(n=2), groin(n=1), lung(n=2) and mediastinum (n=1). Eight cases of SSs originating from lower limbs demonstrated a largish, well-defined, heterogeneous masses with an average size of 6.5 cm. One patient with foot lesion showed a large. illdefined, and heterogeneous mass with adjacent cuneiform and metatarsal invasion. A "triple signal" pattern can be observed on T2WI in four of them. Most of the masses showed lobulated in shape. After administration of contrast agents in seven patients, the tumors displayed annular or marked heterogeneous enhancement. The two lung lesions showed isolated, well-demarcated, and heterogeneous masses with internal multiple nonenhancing regions, representing necrosis or cystic degeneration. One mediastinal tumor with large size and cystic area contained irregular septations and mural nodules within them. Eight patients died of recurrences or metastases after surgery or therapy. Conclusion The diagnosis of SS should be suggested in the adult patient when imaging depicts a largish, well-defined, soft-tissue mass containing area of cystic degeneration in the lower extremity, specially a "triple signal" pattern is detected on T2WI. The key for correct diagnosis is to inosculate imaging to clinicopathological data. FDG PET may be helpful for the assessment of prognosis.