The purpose of this study was to assess the role of dental amalgams and diet upon urinary mercury (U-Hg) excretion. 98 subjects (50 men and 48 women) not exposed to inorganic mercury, for either occupational or environmental reasons, and living in coastal and inland districts of Apulia (Southern Italy) were considered. All the subjects were administered a questionnaire with questions concerning life style, medical history, and occupational activity. Dental amalgams were evaluated with respect to their number and their surface areas. Urinary mercury was measured by the cold vapour atomic absorption technique. Expressed in terms of arithmetic mean, U-Hg excretion was found to amount to 1.03 micrograms/g creatinine (5th and 95th percentile: 0.31 and 2.40; range 0.30-3.25). Multiple linear regression analysis showed that, of the several tested independent variables (dental amalgams, age, body mass index, consumption of tuna, bass, swordfish, etc.), only the number of amalgam fillings (T = 5.25; p = 0.025) and the number of restored surfaces (T = 2.33; p = 0.020) were found liable to affect urinary mercury excretion in a significant manner. In conclusion, the results of this study confirm the primary role of amalgam fillings in affecting urinary mercury excretion in those subjects who are not occupationally exposed to inorganic mercury, The resulting urinary mercury levels can no doubt be taken as the reference values for the population of Apulia.