A 73‒year‒old male had started undergoing hemodialysis due to diabetic nephropathy seven years ago. He was receiving dual antiplatelet therapy, as he had undergone coronary stenting. He was diagnosed with novel coronavirus disease 2019 (COVID‒19) by contact screening and admitted to our hospital. Chest CT only showed a single ground glass opacity; however, prophylactic heparin treatment was started because his D‒dimer level was slightly elevated. Dexamethasone was started on the 4th day of hospitalization, as the patient had had a fever since the second day. Lower back pain appeared on the 6th day and changed to abdominal pain the next day. On the same day, he presented with hypovolemic shock during hemodialysis and progressive anemia; therefore, dialysis was discontinued. Contrast‒enhanced CT showed a huge left retroperitoneal hematoma and contrast medium extravasation. A blood transfusion was started, and angiography was performed, while care was taken to avoid a secondary infection. Angiography revealed bleeding from the 4th lumbar artery, which was successfully treated with coil embolization. The anemia did not progress further, and the patient was transferred to another hospital on the 60th day. COVID‒19 has many thrombotic complications, and prophylactic heparin is often administered that are at high risk of bleeding complications, such as those taking and dialysis patients, careful judgments should be made regarding therapy.