BACKGROUND Acquired haemophilia is a rare coagulation disorder characterized by autoantibodies against coagulation factor VIII leading to severe and potentially life-threatening haemorrhages. The underlying disorder causing the development of an autoimmune phenomenon is not always known, but 10%-15% could be linked to malignancies. Patients with cancer who require surgical resection represent a treatment challenge not solely due to increased risk of bleeding but also due to adverse events of immunosuppressive therapy. CASE SUMMARY We present the case of a 67-year-old man with non-metastatic adenocarcinoma of the distal bile duct who developed concomitant acquired haemophilia a month after having been diagnosed with malignant disease. Haemostasis was established with recombinant activated factor VII, and immunosuppressive therapy was started immediately. An extensive surgical procedure was performed in order to remove the cancer and, therefore, eliminate the inhibitory autoantibodies. Due to a complicated postoperative course, relatively short period of treatment and likelihood of micrometastases, no improvement in the patient’s status was observed. Diagnosis and treatment of acquired haemophilia as well as other coagulation disorders in patients with cancer are discussed. CONCLUSION Prompt diagnosis of acquired haemophilia is required in order to start appropriate treatment and reduce mortality. Among patients with cancer, other causes of abnormal bleeding related to malignancy should be considered.