Background and Purpose: Atypical femoral fracture (AFF) is a severe adverse event associated with long-term use of antiresorptive agent for pharmacological treatment of osteoporosis. Many previously published articles had reported prodromal hip pain associated with long-term use of bisphosphonates before occurrence of AFF; additionally, bone marrow edema might also be demonstrated using MRI during the prodromal phase. However, denosumab, a biological antiresorptive agent, is not yet as well characterized regarding its association with prodromal phase of AFF. Methods: This report retrospectively reviewed a case of 68-year-old housewife experiencing AFF after long-term use of denosumab; bisphosphonates were never prescribed and were never used. Results: This is a case to demonstrate that bone marrow edema can occur during the prodromal phase of AFF with long-term use of denosumab; clinical course from the start of its usage until occurrence of AFF and its sequela were cap-tured. Conclusion: In this case report, crucial importance of early detection along with timely adjustment of medication is emphasized. Although the patient reported had experienced AFF due to lack of prevention, the purpose of this case report is to raise the awareness that AFF can be prevented with timely adjustment of medications.