We analyzed the treatment outcomes of intracranial ependymomas in Korean children aged <18 years. Data for 96 patients were collected from five hospitals. Survival rates were calculated using the Kaplan-Meier method. Log-rank tests for univariate analyses and Cox regression model for multivariate analysis were conducted to identify prognostic factors for survival. The median age of the patients was 4 years (range, 0.3-17.9 years). The median follow-up was 55 months (range, 2-343 months). Age <3 years was an important factor for selecting adjuvant therapy after surgery. Among children aged <3 and ≥ 3 years, adjuvant radiotherapy (RT) was applied to 55 and 84 %, respectively, and adjuvant chemotherapy to 52 and 10 %, respectively. The 5 year local progression-free survival (LPFS), disease-free survival (DFS), and overall survival (OS) rates were 54, 52, and 79 %, respectively. Gross total resection was the most significant prognostic factor for all survival endpoints. Age ≥ 3 years and RT were significant prognostic factors for superior LPFS and DFS. However, the significance of age was lost in multivariate analysis for DFS. LPFS, DFS, and OS were superior in patients who started RT within 44 days after surgery (the median time) than in patients who started RT later in the patients aged ≥ 3 years. Postoperative RT was a strong prognostic factor for intracranial ependymomas. Our results suggest that early use of RT is an essential component of treatment, and should be considered in young children.