Objective To identify the level of functional immunity as measured by the ImmuKnow assay in Chinese stable liver transplant recipients and to correlate these values with the dose and the trough levels of immunosuppressant, and with other clinical parameters of these patients. Methods Functional immune response was assessed by the ImmuKnow assay in 46 blood samples taken from 46 stable liver transplant recipients from Beijing Youan Hospital, Capital Medical University Liver Transplantation Center. Results The average ATP value in these stable liver transplant recipients was 203±114 ng/ml (range: 38.47 ATP ng/ml to 524.06 ATP ng/ml) at 22± 15 month post liver transplantation. There was no correlation either between ImmuKnow ATP values and the tacrolimus trough levels, or between ImmuKnow ATP values and the liver function (P<0. 05). Stepwise multiple regression analysis identified WBC and CD3+, CD3+ CD4+ as independent predictors of ImmuKnow assay levels when age, gender and underlying diagnosis were taken into account (P<0. 05). Five patients who were detected to have active HCV infection had lower ImmuKnow ATP values (<61 ng/ml). Conclusions The Cylex ImmuKnow assay ATP values were lower in Chinese stable liver transplant recipients compared with American patients. Further investigation is required to determine the role of the ImmuKnow assay in tailoring immunosuppressant therapy in liver transplant recipients.