BACKGROUND Rheumatoid arthritis (RA) is a common chronic inflammatory autoimmune disease with the main clinical feature of progressive joint synovial inflammation, which can lead to joint deformities as well as disability. RA often causes damage to multiple organs and systems within the body, including the blood hemostasis system. Few reports have focused on acquired coagulation dysfunction resulting from vitamin K-dependent coagulation factor deficiency associated with RA. CASE SUMMARY A 64-year-old woman with a history of RA presented to our hospital, complaining of painless gross hematuria for 2 wk. Blood coagulation function tests showed increased prothrombin time, international normalized ratio, and activated partial thromboplastin time. Abnormal blood coagulation factor (F) activity was detected (FII, 7.0%; FV, 122.0%; and FX, 6.0%), indicating vitamin K-dependent coagulation factor deficiency. Thromboelastography and an activated partial thromboplastin time mixed correction experiment also suggested decreased coagulation factor activity. Clinically, the patient was initially diagnosed with hematuria, RA, and vitamin K-dependent coagulation factor deficiency. The patient received daily intravenous administration of vitamin K1 20 mg, etamsylate 3 g, and vitamin C 3000 mg for 10 d. Concurrently, oral leflunomide tablets and prednisone were administered for treatment of RA. After the treatment, the patient's symptoms improved markedly and she was discharged on day 12. There were no hemorrhagic events during 18 mo of follow- up. CONCLUSION RA can result in vitamin K-dependent coagulation factor deficiency, which leads to acquired coagulation dysfunction. Vitamin K1 supplementation has an obvious effect on coagulation dysfunction under these circumstances.