The purpose of the pretransplant assessment in lung transplantation is to determine a patient's need for transplant as well as their potential survival post-procedure. In 2005, the UNOS introduced the LAS, a calculation based on multiple physiologic measures to determine need and likelihood for survival. Measures include NYHA class and the 6-MWT. Some adult studies indicate a positive correlation with 6-MWT and waiting list survival. In pediatric/adolescent patients, there are minimal data regarding the predictive value of physiologic markers in either wait list survival or post-transplant outcome. A retrospective cohort study of 60 consecutive lung transplantations from 1990 to 2008 was performed at a pediatric tertiary care facility. Functional pretransplant assessments were abstracted from the medical record and compared with outcomes after transplantation. Results: a 6-MWT of >1000 ft (305 m) prior to transplantation correlated with a shorter ICU stay (7 vs. 11 days, p = 0.046) and fewer days of mechanical ventilation (2 vs. 4, p = 0.04). A pretransplant 6-MWT greater than 750 ft (229 m) correlated with shorter overall hospitalization (37 vs. 20 days, p = 0.03). Measuring pretransplant 6-MWT tests for pediatric patients is valuable in predicting peri-operative outcomes after lung transplantation.