Objective: To compare height standard deviation score (SDS) at start of radiation therapy and at the last follow-up in children with brain tumor treated with CSI. Methods: This study is a retrospective study. Medical records of children aged 3-15 years old, diagnosed with embryonal or germ cell tumor, and treated with 3D conformal radiation therapy (3DCRT) for CSI at Division of Radiation Oncology, Siriraj Hospital between 2006 and 2014 were reviewed. Patient’s demographic data, clinical information, radiotherapy technique, weight and height before the start of radiation therapy and at follow-up were obtained. The height standard deviation score (SDS) was calculated by INMU-Nutri Stat software program. Results: There were twenty one eligible patients. Overall, the latest height SDS was significantly reduced. Mean reduction of the height SDS was 1.24 ± 1.08 (p < 0.001). Four patients (19%) had the latest height SDS < -2. Positive correlation between initial height and the latest height (p = 0.001), and negative correlation between hypothalamicpituitary axis (HPA) mean dose and the latest height (p = 0.02) were found. The patients who received HPA mean dose more than 47Gy tended to have the latest height SDS less than -1.5. Conclusion: Children treated with CSI have significant reduction of height even 3D-CRT was used. The incidence of short stature is 19%. The initial height is strongly related to the latest height. Weak negative correlation of radiation dose to HPA and the latest height was observed.