The purpose of this study was to investigate if enalapril could be administered with cyclosporin A (CyA) to reduce its nephrotoxicity. Sixty rats were divided into five groups: group I, Control group; group II, rats treated with oral enalapril; group III, rats treated with CyA; group IV, rats treated with CyA and enalapril; group V, rats treated with enalapril before the CYA therapy. At the end of the therapy mean serum creatinine concentrations were not statistically different between the groups (P>0.05), in groups treated with CyA there were no statistically significant differences between mean CyA levels (P>0.05), and mean blood urea nitrogen levels of the groups treated with CYA were significantly elevated (P<0.05) compared with groups not treated with CyA. Morphologically acute CyA nephrotoxicity was evaluated by the following features: (1) tubular vacuolization, (2) tubular necrosis, (3) tubular microcalcification, and (4) peritubular capillary congestion. These lesions were scored semiquantitatively on a scale from 0 to 4+. The most common tubular pathology was tubular vacuolization, which was more severe in groups III and IV. Tubular necrosis was most severe in group III. In conclusion, enalapril seems to suppress the severest form of CyA nephrotoxicity, namely tubular necrosis, if administered prior to CyA treatment.