Background/Aims: Cyclosporin A (CsA) stimulates the development of fibrosis. We investigated whether CsA contributes to peritoneal alterations induced by long-term exposure to dialysis solutions. Methods: Ten rats received peritoneal infusion of dialysis solution and oral CsA for 8 weeks. Eight received only the dialysis solution (controls). Peritoneal function was assessed at 8 weeks followed by sacrifice. The number of vessels was counted, fibrosis was assessed and hydroxyproline was determined. PCR was performed for vascular endothelial growth factor (VEGF), connective tissue growth factor (CTGF) and transforming growth factor-β (TGF-β). Results: Histology revealed more fibrosis, hydroxyproline and vessels (thick walled) in CsA-exposed animals. Peritoneal transport was not different. The mRNA content of TGF-β, CTGF and VEGF was higher in CsA. Conclusion: CsA combined with exposure to dialysis solutions was associated with increased peritoneal fibrosis and angiogenesis.