Abstract Purpose To assess the safety of Zoledronic acid (ZOL) and Denosumab (Dmab) administered following hip fracture in a hospital setting. Methods Patients older than 65 years were treated by a Fracture Liaison Service following hip fracture. Generally, patients who had a GFR>35 ml/min, were treated with ZOL, whereas patients who had previously received bisphosphonates or had a GFR between 20-35 ml/min, were treated with Dmab. Adverse events included hypocalcemia (calcium corrected for albumin less than 8.5 mg/d), renal functional impairment (0.5 mg/dl or more increase in serum creatinine) within 30 days of treatment, or a fever (>38˚C) within 48 hours of drug administration. Results Two hundred and twenty-eight and 134 patients were treated with ZOL and Dmab respectively. Mean body temperature was elevated following ZOL administration (0.18 degrees Celsius P<0.001) but remained below 38° Celsius. Hypocalcemia occurred in 18% and 29% of the ZOL and Dmab groups respectively (P=0.009). Renal functional impairment was observed in 9 and 6 patients (4% and 5%) in the ZOL and Dmab group respectively (P=0.8). Pre-treatment calcium above 9.3 mg/dl was associated with a lower risk of post-treatment hypocalcemia (OR 0.30 95% CI-0.13-0.68, P=0.004). While the absolute risk of hypocalcemia was higher in the Dmab group, multivariate analysis did not find that the choice of drug was predictive of hypocalcemia. Conclusion In-hospital parenteral osteoporosis treatment was rarely associated with fever or renal function impairment but was associated with hypocalcemia. Post-treatment hypocalcemia risk did not vary significantly between patients receiving ZOL or Dmab.