Ibrutinib is one of the kinase inhibitors that can be used in the treatment of mantle cell lenfoma (MCL), Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Lymphoma (SLL), Wal- denström’s Macroglobulinemia (WM) and Marginal Zone Lymp- homa (MZL). Although ibrutinib is well tolerated by patients, the cardiovascular side effects of the drug are an important problem. One of the most feared side effects of ibrutinib is atrial fibrillation. The most important concern in atrial fibrillation is thromboembo- lism. It is a known situation that the risk of thromboembolism in cancer patients is higher than the normal population. In patients using ibrutinib, the drug interacts with drugs used in atrial fibril- lation and causes bleeding by disrupting platelet functions on its own, complicating atrial fibrillation management. The purpose of this article is to reveal the ibrutinib-associated atrial fibrillation mechanism and to review the treatment options.