Up to 24 postmenopausal women with osteoporosis who have been on bisphosphonate therapy for one year or more at any point prior to fracture and have sustained an atypical subtrochanteric or diaphyseal fracture will be enrolled. Subjects randomized to the two intervention arms will self-administer a daily SQ injection of the study medication for 12 months. The primary objective is to demonstrate greater radiologic evidence of healing at 10 weeks in patients on immediate teriparatide compared to those on delayed teriparatide who receive therapy six months after fracture. Secondary end points include (1) radiologic healing at 2, 6, 24, and 46 weeks; (2) increased bone density at 6 and 12 months as assessed by dual x-ray absorptiometry (DXA) at the spine, contralateral hip, and femoral neck; (3) quality of life improvements at 10 weeks and 6 months as assessed by quality of life questionnaire and pain score; and (4) differences in biochemical markers of bone turnover in patient with upfront therapy compared to patients with delayed therapy and patients who refuse therapy or for whom teriparatide is contraindicated.