Introduction: Medial malleolar stress fractures are rare injuries resulting from excessive and repetitive stress loads on bone. The incidence rate of these stress fractures varies from ۰.۶% to ۴.۱% of all stress fractures and has been almost exclusively reported in athletes. Typical clinical presentation is a gradual onset of pain and tenderness at the medial malleolus site with a history of long-term physical activity. Presentation: A ۶۰-year-old postmenopausal woman with a gradual onset of pain and point tenderness over the medial malleolus and a history of daily walking for several months. Diagnosis: The initial anterior-posterior and lateral plain radiographs were normal. After the initial conservative medication therapy failed, magnetic resonance imaging (MRI) was obtained. It demonstrated a vertical linear zone of decreased signal intensity originating between the tibial plafond and the medial malleolar junction, which suggested medial malleolar stress fracture. Intervention: We started treatment with a short leg cast and non-weight bearing for six weeks that failed; open reduction and internal fixation were performed under general anesthesia. Outcomes: Six months postoperatively, the pain entirely resolved, and the patient returned to her regular daily physical activity and conducted plain radiographs demonstrating complete union, and no complications occurred. Conclusion: Medial malleolar stress fractures are rare injuries and might be misdiagnosed due to normal initial radiographs. They must be considered in those with gradual onset of pain and point tenderness of medial malleolus, especially with a history of long-term physical activity. Early diagnosis and surgical intervention lead to faster healing and a return to physical activity