Chronic exposure to inorganic mercury can cause kidney injury. Evidence gained from occupational medicine indicates that individuals who are exposed to only environmental sources, including amalgam tooth fillings, are at very little risk. Animal experiments, however, have revealed glomerular lesions of immunologic origin after low-dose exposure to inorganic mercury. In this study, the association between the number of amalgam tooth surfaces, urinary mercury, and proteinuria was explored in a sample of 48 randomly selected, apparently healthy male students who were 17-22 y of age. Presence of any of the following proteins in two separate urine samples was considered to be potentially indicative of any tubular and/or glomerular lesion: albumin, alpha-1-microglobulin (HC-protein), kappa and lambda light chains, and N-acetyl-beta-D-glucosaminidase. No significant relationship was found between any of the proteins and amalgam or urinary mercury. The results of this study did not suggest that amalgam fillings cause kidney dysfunction in humans.