We have reviewed our experience with conversion to tacrolimus after 435 liver transplantations. Tacrolimus was administered as a rescue agent in 33 patients until October 1993. Indications for rescue therapy were: cholestatic forms of severe, steroid-resistant cellular rejection (n = 8), OKT3-resistant cellular rejections (n = 6), cellular rejections in patients suffering from cyclosporin malabsorption (n = 4), late onset cellular rejections (n = 4), early chronic rejections (n = 3), and chronic vascular or ductopenic rejections (n = 8). Response was evident in 29 of the 33 patients (88%), whereas 4 patients (12%) were nonresponsive. Patient and graft survival were 76% and 70%, respectively. Graft loss with or without patient death occurred in three of eight patients suffering from severe, steroid-resistant cellular rejection, in two of six patients with OKT3-resistant cellular rejections, and in five of eight patients undergoing chronic rejection. In severe steroid-resistant cellular rejection, successful tacrolimus rescue therapy corresponded to a significantly lower total serum bilirubin than unsuccessful therapy (12.0 +/- 5.6 mg% vs 29.7 +/- 5.9 mg%, P < 0.05). We conclude that tacrolimus rescue therapy is a safe and efficient alternative for high-risk cases that do not respond to conservative treatment. In severe, steroid-resistant cellular rejection and in chronic ductopenic rejection, conversion to tacrolimus is beneficial only in a limited number of cases. A predictive parameter, which total serum bilirubin may prove to be in severe, steroid-resistant cellular rejection, is needed to select those cases that might benefit more from retransplantation than from conversion to tacrolimus.