In this study, FPIA monoclonal CsA and EMIT Cyc Assays of whole blood were compared among a group of early transplanted patients. Thirty-three subjects who underwent renal transplantation were of age between 15-57. In addition to the whole blood assays, FPIA TDx CsA serum level was also measured in only six of the patients during the first 60 days of posttransplantation. In other patients whose transplant age was between three months and seven years had only FPIA monoclonal CsA and EMIT Cyc'Assay done after taking their single dose of Neoral, which was stabilized during the study. The mean values of the results were compared. Although we did not have sufficient number of subjects in the first group EMIT Cyc Assay results were more compatible than FPIA monoclonal CsA and FPIA TDx CsA. The analysis of EMIT Cyc Assay in the other group of patients, who were taking the same dosage of Neoral resulted in r=0.43 (p<0.01), where as FPIA monoclonal CsA resulted in r=0.34 (p<0.03). The comparison of the two tests results in r=0.92 (p<0.001).