Background: Short term clinical outcomes associated with Ramadan fasting for adolescent with uncontrolled diabetes include hypoglycemia, hyperglycemia with or without the risk of impending ketosis, dehydration, and thrombosis. Aim: This study aims to assess adolescent knowledge related to diabetes management and short term outcomes during fasting Ramadan Design: A descriptive design was used. Setting: This study was conducted at the outpatient diabetic Unit, affiliated to Ain Shams University Hospital Sample: A purposive sample included 50 adolescent with diabetes mellitus who fasting Ramadan; Tools: 1) structured interview questionnaire for adolescents with diabetes during fasting Ramadan. It is composed of Socio-demographic characteristic, Assessment of adolescents' medical health , Knowledge about diabetes and short term outcomes management during Ramadan  2) reported practice checklist.  Results: The present study revealed that near two thirds of adolescents had an unsatisfactory level of knowledge to all items about diabetes. Conclusion: there were statistically insignificant relations between the adolescent's knowledge of diabetes management and short term outcomes during Ramadan. Recommendations: Health education programs about disease and its management  modalities should be provided for diabetic adolescent using new methods of teaching such as computer assisted instructions and home videos.