Purpose Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. Methods The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). Results 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). Conclusion ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR. Acute cellular rejection (ACR) is a common form of allograft rejection in pediatric recipients after lung transplant (LTx). ACR most commonly occurs during the 1st post-transplant year. This study sought to determine if transplant center volume affected ACR-related outcomes in children after LTx. The United Network for Organ Sharing (UNOS) Registry was queried for patients <18 years who underwent LTx in 1987-2020. Cohorts were patients who were treated for ACR during the 1st post-LTx year (ACR group) and who did not experience ACR (non-ACR). Survival of patients who had ACR was compared by LTx center volume defined as average of LTx/year: >5LTx/year (high), >1-≤5LTx/year (medium) and 1LTx/year (low). 1338 patients were included in our analysis with 271 (20.3%) identified as having ACR. Compared to non-ACR, the ACR cohort were older (median 14 [11-16] vs 13 [7-16] years, p<0.001), more commonly female (65.3% vs 57.3%, p=0.016), more commonly diagnosed with cystic fibrosis (62.3% vs 45.5%, p<0.001), and had a higher lung allocation score at LTx (37.3 [34.6-47.8] vs 35.8 [33-42.6], p=0.029). Kaplan-Meier survival of ACR vs non-ACR cohorts trended towards lower survival at 5-yr (37% vs 47%) & 10-yr (25% vs 34%) post-LTx, p=0.06. ACR occurred in 17% of patients at high (n=98/574), 18.5% (n=73/395) at medium, and 27% (n=100/369) at low volume centers. Patients treated for ACR at high volume centers had better post-transplant survival than low volume centers (p<0.001) but similar survival to those at medium volume centers (p=0.081; Figure). No significant difference in survival was observed in medium vs low volume centers (p=0.14). ACR treated within the 1st post-LTx year influences survival of pediatric LTx recipients. ACR incidence was lowest at higher volume centers where post-ACR treatment survival outcomes were also superior. More analysis is needed to determine factors affecting differences in center outcomes regarding ACR.