The primitive neuroectodermal tumors are the second common malignancies among the childhood brain tumors. Theit prognosis are quite variable and the multidisciplinary treatment approach is required. The purpose of our study is to evaluate the factors that can affect overall survival. After the surgery, seventeen patients have received the radiotherapy (median 34.2 Gy to craniospinal region and median 54 Gy to posterior fossa at a 1.5-1.8 Gy daily fractionation dose) and the chemotherapy. The average preoperative tumor volume was 41.5 cm.'. Eight patients were in a standard risk group and the rest was in a high risk group. The mean follow-up time was 27.8 months and the overall survival was three years. It has been found that the overall survival was affected by the unfavorable prognostic factors such as lar ger (>30 cm') preoperative tumor volume, supratentorial location. bein in hi h risk group and more than fifty days radiotherapy treatment. The preoperative large tumor volume and prolonged radiotherapy duration were determined as unfavorable prognostic factors in our study, that differ from the literature data. Due to the limited number of the patients in this study, these results should be confirmed with additional studies with larger patient groups.