Background. Chronic cyclosporine (CsA) nephrotoxicity is associated with renal fibrosis and hyaline arteriolopathy. Fibrogenic cytokines, such as transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF), play a pivotal role in CsA nephrotoxicity. Previous studies have demonstrated the possible role of leukotrienes (LT) in chronic CsA nephrotoxicity. The aim of this study was to examine the possible beneficial effects of LT blockers in attenuating the morphological and histochemical effects induced by CsA in a rat model of CsA nephrotoxicity.