BACKGROUND:Oral anticoagulants present multiple practical problems for patients undergoing chemotherapy. To assess the practice implications of anticoagulation therapy, a review was carried out. METHODS:A review of all patients with cancer treated with warfarin for venous thromboembolism (VTE) over a 1-year-period was carried out. Adverse events and therapeutic efficacy were assessed and the extra volume of work involved in monitoring was quantified. RESULTS:Fifty-five patients with cancer and VTE were treated with warfarin from 07/04 to 06/05. Twenty-one invasive interventions required disruption of anticoagulation. There were eight admissions for haemorrhage. Nine patients died while on warfarin. A total of 1,379 coagulation tests were performed. There were 382 extra dayward visits attributable to warfarin monitoring. On treatment, 13 patients (24%) were changed from warfarin therapy to low molecular weight heparin (LMWH). CONCLUSIONS:This study identifies and quantifies the extra resource utilization with warfarin therapy in patients undergoing chemotherapy.