This document discusses the transplantation of livers from hepatitis C virus (HCV) antibody-positive, HCV RNA-negative donors into HCV-negative recipients at a medical center between 2015-2017. Four cases of HCV transmission were observed. Various hypotheses for the transmission mechanism are discussed, including the possibility of an occult HCV infection or transient low-level viremia in donors. The timing of HCV testing in donors and lack of recipient RNA testing limit conclusions about the transmission mechanism. Taiwan has an estimated HCV antibody-positive rate of 4-5% in the general adult population, equivalent to 400,000-700,000 infected individuals.