Familial hypercholesterolemia is a metabolic disease caused by a mutation in the low-density lipoprotein receptor gene. It carries early atherosclerosis and coronary artery disease risks. Coronary artery disease has been reported 20 times in the pediatric population with familial hypercholesterolemia compared to the normal population. Early diagnosis and treatment may reduce morbidity and mortality. In this article, we present a 16-year-old patient, who followed up for 12 years due to hypercholesterolemia and applied to our hospital due to chest pain, shortness of breath, and palpitation. After a detailed evaluation, we detected critical left and right main coronary artery stenosis, and bypass surgery was performed by cardiovascular surgeons. Early diagnosis of children with familial hypercholesterolemia or patients who have a family history of hypercholesterolemia will allow treatment of the disease and prevention of the complications.