**Abstract**

The success of transplantation depends on multiple factors, but the establishment of immune tolerant milieu is of critical importance. Hepatic environment consists of different cellular populations with prominent capacity to tolerate a huge range of antigens. Among them, regulatory T cells (Tregs) play an important role. They control the strength of immune reactions against non-self antigens and were shown to have an impact on the establishment of immune tolerance in the post-transplantation period. Furthermore, they impact a particular state after transplantation – operational tolerance. The abundant data show that Tregs might be manipulated, which suggests their further implementation as a treatment strategy. Tregs are also a very attractive target as a biomarker in the monitoring of post-transplantation period. Here, we review the particular role of Tregs among the broad spectrum of immune tolerance mechanisms of the liver in the light of the current directions of medical research.

**Keywords:** liver transplantation, regulatory T cells, immune tolerance, biomarker, operational tolerance
