Cyclosporin's role as the leading immunosuppressant for use in transplantation maintenance has been further contested as a result of 2 large, multicentre studies presented at the 16th International Congress of the Transplantation Society (ICTS) [Barcelona, Spain; August 1996]. The studies, which compared the efficacy of the 2 drugs in patients undergoing kidney transplantation, favoured the use of tacrolimus over the original formulation of cyclosporin ‘Sandimmun’. But will tacrolimus be equally advantageous in comparisons with ‘Neoral’, the newer formulation of cyclosporin?