OBJECTIVE To assess current clinical outcomes in children with prenatally diagnosed congenital lung malformations (CLMs) and to identify prenatal characteristics associated with adverse outcomes. SUMMARY BACKGROUND DATA Despite a wide spectrum of clinical disease, the identification of fetal CLM subgroups at increased risk for hydrops and respiratory compromise at delivery have not been well defined. METHODS A retrospective cohort study was conducted using an operative database of prenatally diagnosed CLMs managed at eleven children's hospitals from 2009-2016. Statistical analyses were performed using non-parametric bivariate or multivariable logistic regression. RESULTS Three hundred forty-four children were analyzed. Fifteen (5.5%) fetuses were managed with maternal steroids in the setting of hydrops, and prenatal surgical intervention was uncommon (1.7%). Seventy-five (21.8%) had respiratory symptoms at birth, and 34 (10.0%) required neonatal lung resection. Congenital pulmonary airway malformation volume ratio (CVR) measurements were recorded in 169 (49.1%) cases and were significantly associated with perinatal outcome, including hydrops, respiratory distress at birth, need for supplemental oxygen, neonatal ventilator use, and neonatal resection (p < 0.001). An initial CVR ≤ 1.4 was significantly correlated with a reduced risk for hydrops [area under the curve (AUC), 0.93; 95% confidence interval (CI), 0.87-1.00]. A maximum CVR < 0.9 (AUC, 0.72; 95% CI, 0.67-0.85) was associated with a low risk for respiratory symptoms at birth. CONCLUSION In this large, multi-institutional study, an initial CVR ≤ 1.4 identifies fetuses at very low risk for hydrops, and a maximum CVR < 0.9 is associated with asymptomatic disease at birth. These findings represent an opportunity for standardization and quality improvement for prenatal counseling and delivery planning.