Background: Cardiovascular disease (CVD) is the leading cause of death in people with type 1 diabetes mellitus (T1DM). Objective: To assess the level of Apo B-100 in dyslipidemic children and adolescents with type 1 diabetes in Diabetes Endocrine Metabolism Pediatric Unit (DEMPU). Methods: This case control study was conducted on 40 patients with T1DM with dyslipidemia and 28 healthy controls. Patients were evaluated clinically by full history taking and thorough clinical examination. Full history included; chronological age and residence of the patient, age at the onset of diabetes, duration of diabetes, insulin therapy and family history of diabetes mellitus, hypertension and dyslipidemia. Thorough clinical examination laying stress on the anthropometric measurements (Wt.SDS, Ht.SDS, BMI), early signs of puberty and signs of associated disorders and/or diabetic chronic complications. The records of the patients were reviewed especially for lipid profile, HbA1c for which mean was calculated in the last year, presence of diabetic retinopathy or microalbuminuria. We measured Apo B 100 for all subjects included in the study. Results: serum TC and LDL in the diabetic group is significantly higher than in control group and that, Plasma levels of apo B100 in children with diabetes (71.25±31.69 mg/dl) ) were significantly higher than healthy children (48.88± 11.41 mg/dl). Furthermore, serum apo B100 in the diabetic group correlated significantly to LDL, TC, HDL, last , mean HbA1c%, and duration of diabetes.(best cutoff value for Apo B100 is 53.7 mg/dl). and there was significant difference between diabetics with normal apo B100 and patients with elevated apo B100regarding LDL and mean HbA1c (p value <0.05) and highly significant regarding TC (p value <0.01)but no significant difference regarding age, sex, puberty, anthropometric measurements and family history of diabetes mellitus, hypertension or dyslipidemia. Conclusion: Plasma levels of apoB100 are higher in the dyslipidemic children and adolescents with type 1 diabetes than healthy children Furthermore, serum apo B100 in the diabetic group correlated significantly to LDL, TC, HDL, last, mean HbA1c%, and duration of diabetes.