Introduction: It is considered that many factors may play a role in urolithiasis. Experimental and clinical studies have shown that zinc has an inhibitory effect on urolithiasis. Materials and Methods: In this study, urinary zinc and copper were measured in 27 healthy controls and 30 calcium oxalate stone formers. Results: Urinary zinc excretion was significantly higher (p < 0.001) in stone formers than healthy controls ( 2,575 B 274 and 960 +/- 80 mg/day, respectively). There was no significant difference in urinary copper excretion between healthy controls and stone formers (32.3 +/- 3.5 and 33.3 +/- 3.2 mug/day, respectively). Conclusions: According to our results, the potent inhibitory effect of urinary zinc excretion on urolithiasis could be reviewed. Copyright (C) 2004 S. Karger AG, Basel.