The Congenital Diaphragmatic Hernia Registry (CDHR) was established to collect data on all infants treated at participating institutions with congenital diaphragmatic hernia (CDH) to assess therapy and improve outcome. Since 1995, the CDHR has accumulated data on over 4000 infants. The collective efforts of the CDH Study Group have provided valuable information regarding the efficacy of various therapeutic interventions and have tried to establish predictors of outcome. Because CDH is an uncommon, heterogeneous structural anomaly with a wide spectrum of severity, individual institutions may vary significantly in their experiences and treatment approaches. International multicenter registries, like the CDHR, are useful to provide clinically relevant direction by accumulating far more data on a large patient population than any single institution might.