Paget's bone disease is heterogeneously distributed and several foci of high prevalence have been reported in Europe, United States, Argentina and Australia. The aim of the present work was to determine the ethnic origin of the disease in Buenos Aires using a cross sectional epidemiological study. Sample choice was based on a sampling according to grandparents' nationality. Ninety five percent of Paget patients were of European descent and 5% were non-European, while in the control group the proportion of European descendants is lower: 83% (OR: 3.7; p < 0.007; IC 95%: 1.4-9.7). Within the group of patients with Paget's disease the proportion of Italian and Russian descendants was higher than expected according to the 1914 Argentinean census. The prevalence of Paget's disease among European migrants was higher than in the control group of citizens. Regardless of environmental factors, it is likely that the migrants carried a higher risk of developing the disease.