Zoledronic acid is a parenteral long-acting bisphosphonate that has been used widely in the management of osteoporosis, bone metastasis and malignancy induced hypocalcaemia. Zoledronic acid is well tolerated but rarely severe hypocalcaemia and nephrotoxicity may occur. Here we report a case of 62 years male patient of metastatic Ca prostate who had severe hypocalcaemia after receiving intravenous zoledronic acid and docetaxel. Patient was hospitalized and managed with intravenous calcium supplementation and remained admitted for several days. Post recovery he was again started on zoledronic acid therapy and chemotherapy.