OBJECTIVE: To describe the process and outcomes of local institutional review board (IRB) review for 2 Pediatric Research in Office Settings (PROS) studies. DESIGN: Pediatric Research in Office Settings conducted 2 national studies concerning sensitive topics: (1) Child Abuse Recognition Experience Study (CARES), an observational study of physician decision making, and (2) Safety Check, a violence prevention intervention trial. Institutional review board approval was secured by investigators' sites, the American Academy of Pediatrics, and practices with local IRBs. Practices were queried about IRB rules at PROS enrollment and study recruitment. SETTING: Pediatric Research in Office Settings practices in 29 states. PARTICIPANTS: Eighty-eight PROS practices (75 IRBs). Main Exposure Local IRB presence. MAIN OUTCOME MEASURES: Local IRB presence, level of PROS assistance, IRB process, study participation, data collection completion, and minority enrollment. RESULTS: Practices requiring additional local IRB approval agreed to participate less than those that did not (CARES: 33% vs 52%; Safety Check: 41% vs 56%). Of the 88 practices requiring local IRB approval, 55 received approval, with nearly 50% needing active PROS help, many requiring consent changes (eg, contact name additions, local IRB approval stamps), and 87% beginning data collection. Median days to obtain approval were 81 (CARES) and 109 (Safety Check). Practices requiring local IRB approval were less likely to complete data collection but more likely to enroll minority patients. CONCLUSIONS: Local IRB review was associated with lower participation rates, substantial effort navigating the process (with approval universally granted without substantive changes), and data collection delays. When considering future reforms, the national human subject protections system should consider the potential redundancy and effect on generalizability, particularly regarding enrollment of poor urban children, related to local IRB review.