Epidemiologic data have shown that Paget's disease of bone is common among people of Anglo-Saxon descent, but it is believed to be rare in India and Asia. The worldwide prevalence of the disease shows pronounced geographic and ethnic heterogeneity, and can vary in populations through migration or loss of geographic isolation. The risk to an individual who changes geographic locations, however, is difficult to quantify because the specific genetic or environmental factors responsible for Paget's disease have yet to be completely determined. We describe a case of monostotic Paget's disease in a 59-year-old Asian Indian man, and consider the potential epidemiologic and etiologic influences (moving to an area of higher disease prevalence, role of genetics, viral exposures) that may have increased his risk for the disorder. The patient presented with several months of right anterior leg pain, and was found on examination to have anterior bowing of the tibia as well as warmth and an audible bruit. Radiographs of the tibia demonstrated a V-shaped lucency, enhanced trabecular pattern, and cortical thickening. Whole-body bone scan confirmed monostotic disease with expansile uptake in the tibia, and laboratory data revealed an elevated urinary collagen N-telopeptide that normalized after bisphosphonate treatment, as did his clinical symptoms. In light of the environmental factors that appear significantly to influence the development of Paget's disease, the diagnosis should be considered in patients traditionally considered at low risk for the disorder.