Background The association between institutional volume and outcomes has been demonstrated for cardiac catheterization among adults, but less is known about this relationship for patients with congenital heart disease (CHD) undergoing cardiac catheterization. Methods Within the IMPACT registry, we identified all catheterizations between January 2011 and March 2015. Hierarchical logistic regression, adjusted for patient and procedural characteristics, was used to determine the association between annual catheterization lab volume and occurrence of a major adverse event (MAE). Results Of 56,453 catheterizations at 77 hospitals, an MAE occurred in 1014 (1.8%) of cases. In unadjusted analysis, a MAE occurred in 2.8% (123/4460) of cases at low-volume hospitals (<150 procedures annually), as compared with 1.5% (198/12,787), 2.0% (431/21,391), and 1.5% (262/17,815) of cases at medium- (150-299 annual procedures), high- (300-499 annual procedures), and very-high-volume (≥500 procedures annually) hospitals, respectively, P < .001. After multivariable adjustment, this significant relationship between annual procedure volume and occurrence of an MAE persisted. Compared to low-volume programs, the odds of an MAE was 0.55 (95% CI 0.35-0.86, P = .008), 0.62 (95% CI 0.41-0.95, P = .03), and 0.52 (95% CI 0.31-0.90, P = .02) at medium-, high-, and very-high-volume programs, respectively. Conclusions Although the risk of MAE after cardiac catheterization in patients with CHD is low at all hospitals, it is higher among hospitals with fewer than 150 cases annually. These results support the notion that centers meeting this threshold volume for congenital cardiac catheterizations may achieve improved patient outcomes.