Cancer is the second leading cause of mortality in the world, second only to cardiovascular diseases. Simultaneously cancer mortality has been steadily decreasing due to the development of new chemotherapy and targeted drugs and the improvement of existing treatment protocols. Improving the prognosis of treatment of cancer patients leads to an unexpected result - more patients are faced with side effects of cancer treatment. Cardiotoxicity, including arrhythmia, has become a significant factor to reduce the effectiveness of cancer patient’s treatment. Atrial fibrillation is frequent and persistent a rhythm disorder, affecting all categories of patients, especially the elderly. An association between these two conditions can be expected, considering the fact that in old age the prevalence of malignant neoplasms and comorbid pathology predisposing to the onset of AF is high. Therefore, AF may be an additional factor negatively influencing the prognosis and treatment tactics in patients with malignant neoplasms. A comprehensive search was conducted using the keywords “cancer”, “atrial fibrillation” and “cardiotoxicity” using the PubMed, Scopus and Cohrane databases. We reviewed publications having the relationship between AF and cancer. The literature review considered 61 publications on the prevalence of AF in cancer patients, classification, mechanisms of development, the effect of anticancer drugs and other treatment methods on this group of patients. Analyzed articles include clinical guidelines, consensus expert opinions, systematic reviews, meta-analyzes, and previously published reviews of the literature. The problem of cardiotoxic complications diagnostics is evaluated separately, incl. arrhythmias, and their monitoring in cancer patients. Therefore, the direction of medicine named "Cardio-oncology" comes to the fore. Interdisciplinary interaction will allow identify cardiotoxic manifestations at the subclinical stage and optimize anticancer treatment.