Background: Carbohydrate content estimation is one of the techniques in diet management that can provide flexibility in choosing food and can help adolescents with type 1 diabetes mellitus (T1DM) to identify blood glucose patterns. Dietary regulation, especially monitoring of carbohydrate intake, is the main determinant of post-meal blood glucose in T1DM. Aim: The aim of this study was to assess the effect of carbohydrate content estimation among adolescents with type 1 diabetes on their glycemic control. Research Question: What is the relation between carbohydrate content estimation among adolescents with type 1 diabetes and their glycemic control?. Setting: The study was conducted in the outpatient Children's Diabetes Clinic, Children's Hospital, Ain Shams University. Subjects: A sample of 81 adolescents with type 1 diabetes between 12-18 years of age. Data collection tools: 1) Diabetic adolescent assessment sheet (by interview) included the studied adolescents' characteristics, diabetes history and physiological assessment, 2) Ped Carb Quiz (PCQ) to assess the studied adolescents' carbohydrate recognition and insulin dosing accordingly. Results: The results of this study revealed that less than two thirds had been previously hospitalized due to DKA, half of them had HbA1c 8 - <10 % with mean HbA1c 9.7 ± 2.343% and total PCQ score meanX̄±SD was 32.03±10.34. Conclusion: It could be concluded that adolescents with type 1 diabetes had a low level of recognition of carbohydrate content estimation and there was a non-significant correlation between glycemic control and their total PCQ score. Recommendation: Enhance the awareness of the adolescents with type 1 diabetes about carbohydrate content estimation.