Background: Carbohydrate content estimation is the nutritional therapy of choice in T1DM, which allows flexible food choices and adolescents may consume any food in a healthy eating plan. However, adjusting the insulin dose to carbohydrate intake could produce potential improvement in glycemic control

Aim: The aim of this study was to evaluate the effect of carbohydrate content estimation on adolescents' glycemic control. Research Design: Quasi experimental (pretest - posttest) design was used to conduct this study .setting: The study was conducted in outpatient Children Diabetes Clinic/Children’s Hospital/Ain Shams University.

Subjects: A Convenient sample included 81 adolescents with type 1 diabetes aging from 12:18 years. Data collection tools: First tool, diabetic adolescent assessment sheet to gather data related to adolescents’ characteristics, illness history and physiological assessment, second tool was, Ped Carb Quiz (PCQ) to assess the studied adolescents’ carbohydrate recognition and insulin dosing.

Results: The results of this study revealed that there was a highly significant difference between total carbohydrate recognition domain and insulin dosing domain pre and post carbohydrate content estimation and also there was significant difference pre-prandial and post-prandial pre and post carbohydrate content estimation.

Conclusion: it can be concluded that the implementation of carbohydrate content estimation affected positively the adolescents' glycemic control. Recommendation: Enhance the awareness of the adolescents with type 1 diabetes about carbohydrate content estimation.