The aims of this study were to evaluate: (1) bioequivalence between Imin® (test) and Ne® (reference) in healthy volunteers, (2) efficacy, safety and need for dose adjustments by converting renal transplant recipients from Ne to Imin. At first step,18 healthy volunteers (25±5 years, 71.2±8 kg) after an overnight fast of 12 hours received assigned treatment (test or reference, 200 mg single dose) in a cross over fashion with a washout period of 14 days. The blood samples were drawn at different times after drug administration. Cyclosporine blood concentration was measured by HPLC using UV detector. With the rational behind the safety of usage of the drug,renal transplant patients with established transplant programs who were taking stable doses of Ne, selected from 2 renal transplant center in Iran, randomly in an open-label manner. They were converted from Ne to Imin based on a 1:1 dosing equivalency. Cyclosporine trough levels and changes in serum creatinine, lipid profile,electrolytes and uric acid were measured before and periodically after conversion for 6 months. 90% confidence interval on the ratio of test/reference was within the acceptable limits of 0.8-1.25. Relative bioavailability of Imin in healthy subjects was 99.0%. 41 patients were included in data analysis. There was no statistically significant difference in cyclosporine concentration and serum creatinine following conversion to Imin in renal transplant patients. There were no reports of major toxicity, graft rejection and no need for dosage adjustment related to Imin. Single doses of Ne and Imin are bioequivalent in healthy subjects. Renal transplant recipients maintained on Ne can be safely and effectively converted to Imin on a 1: 1conversion ratio.