OBJECTIVE This study aims to document the efficacy of zoledronic acid by comparing bone densities and markers of bone turnover, in patients with osteoporosis. METHODS Bone mineral density (BMD) and urinary N-telopeptide, a marker of bone turnover, were compared before and after treatment with intravenous zoledronic acid. RESULTS 52 participants had atleast two doses of zoledronic acid over 36 months. Significant increases in BMD were found in the spine (t=4.38, P<0.01) and decrease in bone turnover marker N-telopeptide (t=3.30, P=0.002). Small but significant correlations were determined between prior steroid use and change in BMD in the spine (r=0.35, P<0.05), and family history of osteoporosis and change in BMD in the right femur (r=0.38, P<0.05). CONCLUSION Annual infusions of zoledronic acid for at least two years, revealed a significant increase in bone density at the spine and a decrease in urinary N-telopeptide in patients treated at our center.