Background & aims: Frailty is prevalent in liver transplant (LT) candidates. It is considered an independent predictor of adverse outcomes pre- and post-transplant according to data obtained in the United States. We aimed to externally validate the liver frailty index (LFI) in a multicenter cohort of LT candidates. Methods: Outpatients with cirrhosis were prospectively recruited from five Spanish centers (2018-2020). Patients were defined as "frail" by an optimal cut-off of LFI ≥4.5. Patients were followed for at least 6 months to study associations of pre-LT frailty with pre- and post-transplant mortality, length of hospital and intensive care unit (ICU) stays, risk of early (<30 days) and late (30-90 days) post-transplant complications, retransplantation and cardiovascular events. Results: Of 212 patients included, 45 patients (21%) were frail pre-LT, and the median LFI was 3.9 (IQR 3.5-4.4). After a median waiting time of 78 days, 2% died or were delisted for clinical worsening. The LFI at baseline was not predictive of mortality/delisting in LT candidates in univariable or multivariable analyses after adjusting for age and MELD-Na score (hazard ratio 1.48; p = 0.586). In contrast, compared to non-frail patients, frail LT candidates had a significantly higher length of hospital stay (9 vs. 13 days; p = 0.001) and rate of early (<30 days) post-transplant complications (55% vs. 100%; p = 0.021). Conclusions: In the context of a short LT waiting time, frailty does not impact pretransplant mortality and/or delisting. In contrast, LT frailty is predictive of higher post-transplant complication rates and length of hospital stay. Whether strategies aimed at pre- and/or re-habilitation are beneficial in settings with short waiting times needs to be confirmed in prospective studies. Impact and implications: Literature is scarce on the actual impact of physical frailty on adverse outcomes in the liver transplant scenario outside North America. Evidence-based justification to extend the use of objective frailty tools in the decision-making processes in other liver transplant settings is needed. This study is the first to evaluate the predictive value of the liver frailty index in outpatients in the European liver transplant setting, showing that in a low MELD, high access system, frailty does not impact pretransplant mortality and/or delisting but is predictive of higher complication rates and longer post-transplant length of stay. In practical ways, physicians should consider physical frailty as a vital sign to be measured systematically and routinely during clinic visits; researchers are encouraged to initiate prospective studies to evaluate the benefit of applying strategies aimed at pre- and or re-habilitation in liver transplant settings with short waiting times.