This multicenter study evaluated end-of-surgery serum lactate concentration as a predictor of postoperative outcomes in patients undergoing liver resection. Using data from 519 patients, the study identified lactate concentration cut-offs that predicted high clinical risk scores, 90-day mortality, and severe morbidity. Models including lactate concentration showed improved accuracy over those without. Validation in 466 additional patients confirmed lactate concentration as an important predictor, especially for clinical risk and mortality. Pre- and intraoperative factors like diabetes, major hepatectomy, and transfusion predicted elevated lactate concentrations. The study concluded lactate is a reliable early indicator of postoperative outcomes after liver resection.