Background: Type 1 diabetes mellitus leads to significant cardiovascular risk through various mechanisms. Intensified insulin therapy is commonly required to achieve adequate glycemic control and reduce HbA1c. However, when insulin dose increases, it might increase insulin resistance and body weight, which directly affecting the cardiovascular profile. Objective: We aim in this literature review to address the role of adding metformin to insulin therapy to limit the cardiovascular effect, insulin resistance and improve glycemic control in pediatric age. Method: We searched in the PubMed database for relevant articles using the following Mesh words: Metformin - Type 1 diabetes mellitus, pediatrics - Cardiovascular risk. Conclusion: Metformin was found to has promising cardiovascular protection when adding to insulin therapy. However, the impact of metformin in type 1 diabetes mellitus glycemic control is controversial, and further multi-systemic randomized clinical trials are recommended to address this issue.