This study was to determine the effects of Sodium-N-[4-methoxybenzyl]-D-glucamine-N-dithiocarbamate(MeOBGDTC) on the nephrotoxicity of mercury and histopathological change in rats pretreated with mercuric chloride 48h earlier. In a firsts experiment, 3 groups were given a single injection i.p. of 3.5 micromol/kg of HgCl2 mixed with 1microCi of 203Hg2+ in a final volume of 0.5ml of physiologic saline. Subsequently the rats also received the chelator, 1 mmol/kg of MeOBGDTC, at 1h in group 2 (HgCl2-MeOBGDTC 1h) and 12h in group 3 (HgCl2-MeOBGDTC 12h) after injection of mercuric chloride. The results showed that the injection of chelating agent at 1h after mercury injection significantly decreased mercury level in plasma. But not significant in renal cortex. In a second experiment, rats were divided into 4 groups, one group was control group, others were mercury injected group. MeOBGDTC was also administered to mercury-injected rats as described above. The changes in renal function were determined by measurement of proteinuria, plasma creatinine and urinary osmolality. The results showed that the injection of mercuric chloride increased the excretion of urinary protein and plasma creatinine, and decreased the urinary osmolarity. However, the injection of chelating agent at 1h after mercury injection significantly decreases the toxic effects of mercury. Finally, histopathological change at the light microscopic level was comparable effect of chelating agent on nephrotoxicity of mercury. Minimal morphological alterations were seen in kidney of rats of HgCl2-MeOBGDTC 1h. The HgCl2-MeOBGDTC 12h caused necrotic change of the proximal tubule at cortical-medullary junction. These changes were more common and more severe at the HgCl2 alone.