Teriparatide is an anabolic osteoporosis therapeutic agent that can improve healing after fractures and periodontal surgeries. Clinical studies investigating the effects of teriparatide on the osseointegration of titanium implants have not been performed. We conducted an open-label randomized controlled feasibility study and included 24 individuals with edentulous lower jaws. The participants received 2 study implants in the mandible during interforaminal dental implant surgery. They were randomly assigned to receive either 20 mu g of teriparatide once daily for 28 days or no treatment. Study implants were retrieved from 23 participants after 9 weeks and were subjected to histomorphometric analyses. Endpoints were new bone-volume-per-tissue-volume (NBV/TV) and new bone-to-implant-contact (NBIC). We report here that median values of NBV/TV in the control and the teriparatide groups were 15.4% vs. 17.6% in the periosteal compartment, 11.3% vs. 16.5% in the cortical compartment, and 7.3% vs. 12.0% in the medullary compartment, respectively. NBIC median values in the control and the teriparatide groups were 3.3% vs. 4.1% in the periosteal compartment, 5.0% vs. 4.4% in the cortical compartment, and 0.3% vs. 1.4% in the medullary compartment, respectively. The results provide the first histological data on the osseointegration of titanium study implants in individuals treated with teriparatide. ClinicalTrials. gov number, NCT00089674.