Heart transplantation (HT) is the gold standard for managing end-stage heart failure. Multiple quality metrics, including length of stay (LOS), have been used in solid organ transplantation. However, limited data are available regarding trends and factors influencing LOS after pediatric HT. We hypothesized that various donor,peri-transplant and recipient factorsaffectLOS after pediatric HT. Weanalyzed patients <18years at time of HT from January 2005 to December 2018 in thePediatric Heart Transplant Society database, and examined LOS trends, defined prolonged LOS (PLOS = LOS>30days after HT), identified factors associated with PLOS and assessed outcomes. Of 4827 patients undergoing HT, 4414 patients were discharged and included for analysis. Overall median LOS was 19days[13,34]. Median LOS was longer in patients with congenital heart disease(CHD = 25days[15,43] than with cardiomyopathy(CM = 17days[12,27] across all ages. Median LOS in age <1year was 26-days[16,45.5] and in age >10year was 16days[11,26]. PLOS was seen in 1313 patients(30%). Patients with PLOS were younger, smaller and had longer CPB times. There was no difference in utilization of VAD at HT between groups, however, ECMO use at listing(8.45% vs 2.93%,p < 0.05) and HT was higher in the PLOS group(9.22% vs 1.58%,p < 0.05). PLOS was more common in patients with previous surgery, CHD, single ventricle physiology, recipient history of cardiac arrest or CPR, end organ dysfunction, lower GFR, use of mechanical ventilation at HT and Status 1A at HT. We present novel findings of LOS distribution and define PLOS after pediatric HT, providing a quality metric for individual programs to utilize and study in their practice.