Objective: To determine types of complications and risks associated with pedatric cardiac catheterization in the current era. Background: Pedatric cardiac catheterization is an important diagnostic and therapeutic tool. Although in the last decade, there have been significant improvements in technology and equipment, the risk for complications remains, adversely effecting outcomes. Design: The clinical records of 11,073 children undergoing cardiac catheterizations between January 1994 and March 2006 were reviewed to identify procedures associated with complications within the first 24 h after catheterization. All children's electronic and paper chart records were reviewed to obtain demographic, procedural, and treatment data. Results: A total of 858 (7.3%) complications (classified as major or minor) occurred in 816 studies (510 males, 63%), in children ranging in age from 8 h to 20 years (median 4.13 years). There were 195 major (22%) and 663 (78%) minor complications. Vascular complications represented the majority (n = 278; 32.4%) and were major in 53 instances (P < 0.0001). Twenty-five children died within 24 h (0.23% of total case numbers). Independent risk factors for a complication included young patient age (<6 months), male gender, inpatient status, and year of catheterization. Conclusions: Complications continue to be associated with pedatric cardiac catheterization, although overall incidence appears to be decreasing. Patient age, gender, and inpatient status continue to be risk factors for morbidity and mortality. Efforts at improving equipment for flexibility and size, and developing strategies for the use of alternative methods for catheter access should be encouraged. © 2008 Wiley-Liss, Inc.