Background We aimed to evaluate the effects of interfacility pediatric critical care transport response time,physician pres-ence during transport,and mode of transport on mortality and length of stay (LOS) among pediatric patients.We hypoth-esized that a shorter response time and helicopter transports,but not physician presence,are associated with lower mortality and a shorter LOS.Methods Retrospective,single-center,cohort study of 841 patients (＜ 19 years) transported to a quaternary pediatric inten-sive care unit and cardiovascular intensive care unit between 2014 and 2018 utilizing patient charts and transport records.Multivariate linear and logistic regression analyses adjusted for age,diagnosis,mode of transport,response time,stabiliza-tion time,return duration,mortality risk (pediatric index of mortality-2 and pediatric risk of mortality-3),and inotrope,vasopressor,or mechanical ventilation presence on admission.Results Four hundred and twenty-eight (50.9％) patients were transported by helicopter,and 413 (49.1％) were transported by ambulance.Physicians accompanied 239 (28.4％) transports.The median response time was 2.0 (interquartile range 1.4-2.9)hours.Although physician presence increased the median response time by 0.26 hours (P =0.020),neither physician presence nor response time significantly affected mortality,ICU length of stay (ILOS) or hospital length of stay (HLOS).Helicopter transports were not significantly associated with mortality or ILOS,but were associated with a longer HLOS (3.24 days,95％ confidence interval 0.59-5.90) than ambulance transports (P =0.017).Conclusions These results suggest response time and physician presence do not significantly affect mortality or LOS.This may reflect the quality of pre-transport care and medical control communication.Helicopter transports were only associ-ated with a longer HLOS.Our analysis provides a framework for examining transport workforce needs and associated costs.