BACKGROUND The Fried frailty phenotype is associated with morbidity and mortality in lung transplant (LTx) candidates, but its clinical application and association with post-transplant outcomes are not well defined. We assessed 2 alternate frailty indices in LTx candidates and evaluated associations of frailty with early post-transplant outcomes and 1-year mortality. METHODS Frailty was prospectively evaluated in 50 LTx candidates using the Fried and 2 alternate phenotypic indices, one using variables readily available to clinicians and one using variables from an existing data set. Agreement between indices and associations with related measures were assessed to establish validity. The data set index was then applied retrospectively to 221 LTx patients. Post-transplant outcomes were compared between frail and non-frail patients using t-tests and multivariable regression analysis. RESULTS Frailty prevalence among the 3 indices was 26% to 30%, and the κ agreement was 0.38 to 0.41. All indices had moderate correlations with London Chest Activity of Daily Living (r = 0.48–0.62) and Short-Physical Performance Battery (r = –0.43 to –0.52). In the retrospective cohort, frail LTx candidates had a worse St. George's Respiratory Questionnaire total score (73 ± 12vs 62 ± 12, p < 0.001). Frail candidates had a larger improvement with transplant in the St. George's Respiratory Questionnaire (–52 ± 19vs –43 ± 18, p = 0.002) and 6-minute walk distance (191 ± 119vs 129 ± 94m, p = 0.001). Frailty was not associated with hospital length of stay or 1-year mortality. CONCLUSIONS There was good construct validity and acceptable agreement among the frailty indices. Despite significant disability pre-transplant, frail LTx candidates derived significant benefit with transplantation.