Purpose: The aim of this study was to evaluate treatment outcome, survival data and prognostic factors in patients with uterine sarcoma treated by postoperative radiotherapy. Materials and Methods: The records of 46 patients treated between 1993 and 2003 were reviewed. Median age was 55 (range 31-75). There were 21 mixed mullerian tumors, 12 leiomyosarcomas, 11 endometrial stromal sarcomas and two adenosarcomas. According to FIGO classification 65.2% were Stage I, 17.4% Stage II, 13% Stage III and 4.3% Stage IV. All patients received external radiotherapy with 1.8 Gy daily fractions up to 50.4-64 Gy (median 50.4 Gy). Intracavitary brachytherapy was applied to 39 patients. Twelve patients received adjuvant chemotherapy. Results: Median follow-up time was 48 months (6-144 months). Seventeen patients (37%) developed distant metastases and one patient had local failure. Five-year overall, disease-free and local recurrence-free survival rates were 57.8%, 60.5% and 97.8%, respectively. Univariate analysis demonstrated that stage (p = 0.011), histologic subtype (p = 0.010), tumor size (p = 0.044), positive peritoneal cytology (p = 0.006) and the use of chemotherapy (p = 0.005) had a significant effect on overall survival. Prognostic factors influencing disease-free survival were stage (p = 0.009), positive peritoneal cytology (p = 0.000) and the use of chemotherapy (p = 0.002). The only prognostic factor affecting local control was stage (p = 0.000). Conclusion: Postoperative radiotherapy seems to be an effective adjuvant treatment providing high local control rates in uterine sarcomas. However its efficacy should be clarified by randomized trials. The important prognostic factors influencing the treatment results were stage, histologic subtype, tumor size and positive peritoneal cytology.