Some reports suggest that the prevalence and severity of gingival overgrowth (GO) is lower in patients taking tacrolimus (Tcr) than in those taking cyclosporin A (CsA). The present study was conducted to determine the prevalence and severity of GO in a group of renal transplant recipients treated with Tcr in comparison to those treated with CsA and to evaluate the risk variables associated with the development of GO in these two drug regimens.