Calcineurin inhibitor-related renal toxicity affects patient and graft survival in transplant recipients. This study aimed to determine whether sirolimus is effective and safe in treating renal insufficiency related to tacrolimus after liver transplantation. Tacrolimus for primary immunosuppression was used in 16 patients after liver transplantation. Patients with a creatinine level higher than 132.6 micromol/L were eligible for conversion to sirolimus. Simultaneously, the dose of tacrolimus was decreased to half. Blood urea nitrogen, creatinine, tacrolimus level, liver function and rejection episodes were monitored dynamically. All patients showed improvement of renal function after conversion to sirolimus. Blood creatinine level was reduced from 146.8+/-92.4 to 105.3+/-71.3 micromol/L (P<0.05). One patient had an acute rejection episode that was successfully treated with pulsed corticosteroids and low-dose tacrolimus. The side-effects of sirolimus included hyperlipidemia (4 patients) and leukocytopenia (2). Sirolimus can be safely used in liver transplant recipients suffering from tacrolimus-related renal insufficiency.