The present case describes an atypical femur fracture in a patient, who had not previously been treated with bisphosphonate. The patient fulfilled the specific characteristics for an atypical fracture that have recently been suggested by an international expert group. For 15 years after her menopause the patient had been treated with oestrogen. Prospective studies to determine the frequency and pathogenesis of these fractures in patients treated with bisphosphonate and in bisphosphonate naïve patients are suggested.