Background/AimsTo investigate the association between tacrolimus (TAC) blood concentration and the risk of post-transplantation diabetes mellitus (PTDM) development after living donor liver transplantation (LDLT). MethodsThis study reviewed the clinical data of 158 adult LDLT recipients. A cut-off of mean trough concentration of TAC (cTAC) value at the sixth month postoperatively was identified using a receptor operating characteristic curve. Other clinical complications rates were compared between different cTAC groups. ResultsThirty-four (21.5%) recipients developed PTDM during follow-up period. Recipients with PTDM suffered lower 1-, 5- and 10-year overall survival rates (85.2%, 64.9%, and 55.6% vs 92.4%, 81.4%, and 79.1%, p < 0.05) and allograft survival rates (87.9%, 76.9%, and 65.9% vs 94.1%, 88.5%, and 86.0%, p < 0.05) than those without PTDM. The best cut-off value of mean cTAC was 5.9 ng/mL. Recipients with higher cTAC (>5.9 ng/mL) were more likely to develop hyperlipidemia (39.6% vs 21.9%, p < 0.05), cardio-cerebral events (7.5% vs1.0%, p < 0.05), and infections (37.7% vs19.0%, p < 0.05) than recipients exposed to low cTAC (≤5.9 ng/mL). However, the two groups showed no difference in the incidence of acute and chronic rejection. ConclusionHigher mean cTAC at the sixth month postoperatively is related to increased risk of PTDM in LDLT recipients.