Paget’s disease of bone (osteitis deformans) is a benign focal disorder of accelerated skeletal remodeling. Either a single bone (monostotic) or multiple bones (polyostotic) can be affected. In patients with suspected Paget’s disease plain radiographs of the suspicious regions of the skeleton are recommended. The initial biochemical evaluation of a patient should be done using serum total ALP (alkaline phosphatase) or with the use of a more specific marker of bone formation: PINP (intact N-terminal type 1 procollagen propeptide) or CTX (cross-linked C‑telopeptide). Treatment with a bisphosphonate is recommended for most patients with active Paget’s disease who are at risk for further skeletal and extraskeletal complications. A single dose of 5 mg i.v. zoledronate as the treatment of choice in patients without contraindications is suggested. Oral bisphosphonates are less potent when compared to zoledronate. Treatment with an antiresorptive agent induces a more rapid decrease in resorption markers compared to formation marker. Measurement of total ALP or other baseline disease activity markers (e. g. CTX) at 6 to 12 weeks, when bone turnover will have shown a substantial decline, is an acceptable and cost-effective option. Maximum suppression of high bone turnover may require measurement at 6 months after administration. In patients with increased bone turnover, biochemical follow-up is recommended to be used as a more objective indicator of relapse rather than symptoms. The prolonged response after zoledronate treatment should be assessed every 1–2 years after normal bone turnover. With less potent drugs, every 6 to 12 months is appropriate.