Background: School Health Program (UKS) is agent to promote and increase health status of school children. Headmaster have responsiblility to monitoring school health children, including nutritional status. Objectives: to asses the effectiveness of a short course on knowledge and skills of UKS's teachers in the assessment of children nutritional status. Methods: This was a before after experimental quasy, in Yogyakarta in 2015. Intervention was a short course 20 hours designed to develop the knowledge and skill of UKS's theacher. Subject were 37 UKS's teachers in Sleman Regency, with criterian complete attending. Data were analyzed by t-test using SPSS. Results: Most of the respondents were public elementary school (68.6%), male (59.4%), 31-40 years old (34.4%), sports teachers (65,5%), managing UKS for 5 years (37.5%), never got similar short course (94.8%). There were an increase of knowledge and skills by 4.9±3.2 and 3±2.8 respectively, statistically significant. Conclusion: The study provides evidence for effectivenes to increase knowledge and skills UKS's theachers in monitoring nutritional status of children.