Synovial sarcoma is a rare type of sarcoma with poor prognosis. Data on relevant prognostic factors are inconsistent. The objective of this study was to determine the independent prognostic factors that govern local recurrence, distant metastasis and overall survival. A retrospective analysis of 51 patients treated for localized synovial sarcoma at a single institution by a multidisciplinary/multimodality approach over a period of 12 years. Patients, tumor and treatment characteristics were collected including age, sex, tumor site, location, depth, size, status of margins, histology subtype and involvement of bone or lymph nodes. Type of surgery, adjuvant chemotherapy and radiotherapy were also examined. The endpoints analyzed were local recurrence-free survival (LRFS), metastasis-free survival (MFS) and overall survival (OS). Median age of patients was 26 years (range 3-64 years) with 73 % above the age of 20 year. All patients received surgery, 57 % received adjuvant radiotherapy and 45 % adjuvant chemotherapy. The median survival was 111 months, and 5-year OS was 73 %. Deep seatedness of the tumor was linked to OS as the only independent risk factor. Twelve patients had local recurrence, and the 5-year LRFS was 61 %. Multivariate analysis determined negative margins and adjuvant radiotherapy as independent predicting factors for LRFS. Five-year MFS was 48 %; multivariate analysis identified monophasic subtype and site other than lower extremity as the only independent factors associated with inferior MFS. The most important factors that govern LRFS and MFS are negative margins and adjuvant radiotherapy for LRFS and tumor histology and site for MFS, while deep seatedness of the tumor is the sole independent factor that governs OS.