Prescription of anticoagulants (ACs) in patients with cancer and atrial fibrillation (AF) is challenging and the impact on survival is not defined.In this study data prospectively collected in Oncology Units were retrospectively evaluated. Among 4664 patients admitted for malignancy, 394 patients (8.4%) had documented AF (mean age of 74 ± 9) and AC was prescribed to 155 patients (40%). Neither the type of cancer, the stage of the disease (metastatic or not) nor the ongoing treatments were significantly associated with prescription of AC, which was independently associated with BMI (OR 1.10; CI 95% 1.03–1.17; p = .003), valvular heart disease (OR 3.76; CI95% 1.59–8.87; p = .002), and previous venous thromboembolism (OR 6.67; 95%CI 2.67–16.70; p