A 31-year-old man with mild hemophilia B developed a herniated disc treated with prednisolone for back pain. Surprisingly, hemostasis result tests performed before epidural infiltration were a normal activated partial thrombin time at 36.1 s. (normal range 27.9–37.7 s.) and factor IX (FIX) level 76% (normal range>70%), 13 days after prednisolone introduction. After a second control with a normal FIX level and a second genetic confirmation of hemophilia, no FIX concentrates was administered to perform the infiltration, which occurred without hemorrhagic complication. This new case of FIX normalization showed the necessity to have a perfect knowledge of patient’s treatment to avoid misdiagnosis and a temporary normal hemostasis permit to perform epidural infiltration without replacement therapy.