Objective: Obstructive sleep apnea syndrome (OSAS), a sleep-related breathing disorder, is characterized by apnea and hypoapnea. In patients with OSAS, ischemic stroke may have various causes such as large-vessel atherosclerosis and cardioembolism. OSAS is one of the risk factors of atherosclerosis, and it is thought to increase the risk of ischemic stroke by triggering atherosclerosis. Many studies have shown the relationship between OSAS and cardioembolic stroke. Ischemic stroke is a heterogeneous group of diseases caused by many complex mechanisms and may show ethnic and racial differences. This study aimed to determine the etiology and risk factors of ischemic stroke in the patient group diagnosed with OSAS in our population.