The exposure to hexavalent chromium is often known to cause acute renal failure. It has been found that nonenzymatic antioxidants and the induction of heme oxygenase 1 have protective effects against nephrotoxicity induced by potassium dichromate in vivo. In this work, the effect of stannous chloride, an inducer of heme oxygenase 1, on potassium dichromate-induced toxicity in proximal tubular epithelial cells was studied. Hexavalent chromium levels, peroxynitrite content, reduced thiol content, heme oxygenase activity, reactive oxygen species production, and stannous chloride scavenging capacity were measured. It was found that stannous chloride protects proximal tubular epithelial cells from potassium dichromate-induced cell death. The decrease in extracellular and intracellular hexavalent chromium concentration, the induction of heme oxygenase 1, and the ability to scavenge reactive oxygen species and peroxynitrite are involved in the mechanism by which stannous chloride protects proximal tubular epithelial cells from potassium dichromate-induced toxicity.