In this study, the lead, cadmium, nickel, and aluminum concentrations were analyzed in inner nucleus and outer crust parts of various kinds of urinary calculi, and the results obtained were statistically compared. Significant differences were found among the element concentrations in the different stone groups. In general, higher element concentrations were found in the nuclei as compared with the crust parts. In addition, some significant intra- and intercorrelations were established among the elements analyzed. The results suggest that some trace elements, including lead, cadmium, nickel, and aluminum, together with other factors may have as yet no clarified functions in the stone precipitation process in the urinary tract. Copyright (C) 2002 S, Karger AG, Basel.