Medication-related osteonecrosis of the jaw (MRONJ) is a serious pathological condition that usually results from anti-resorptive or anti-angiogenic drugs. We aimed to report an unusual MRONJ in a female patient due to long-term simvastatin administration. A 48-year female was referred to the Department of Oral and Maxillofacial, Mashhad Dental School, Mashhad, Iran in Dec 2019. She complained of pain, swelling, and infection in the right mandibular area with a history of extraction. Based on medical history, the patient received 40 mg of simvastatin daily for ten years to control hypercholesterolemia. According to clinical and radiographic examinations, as well as previous medical and dental records, the lesion diagnosis was detected as MRONJ. Moreover, histopathological examination of the lesion confirmed our clinical diagnosis. The necrotic bone was removed with caution. The PRF was then inserted, and the flap was sutured without any tension. No complications were observed on following-up, and all symptoms were discontinued. There was a correlation between the administration of high-dose simvastatin and MRONJ. Moreover, more clinical investigation with larger sample sizes is suggested.