Abstract. Multicenter clinical trials require approval by multiple local institutional review boards (IRBs). The Multicenter Airway Research Collaboration mailed a clinical trial protocol to its U.S. investigators and 44 IRBs ultimately reviewed it. Objective: To describe IRB responses to one standard protocol and thereby gain insight into the advantages and disadvantages of local IRB review. Methods: Two surveys were mailed to participants, with telephone follow-up of nonrespondents. Survey 1 was mailed to 82 investigators across North America. Survey 2 was mailed to investigators from 44 medical centers in 17 U.S. states. Survey 1 asked about each investigator's local IRB (e.g., frequency of meetings, membership), whereas survey 2 asked about IRB queries and concerns related to the submitted clinical trial. Results: Both surveys had 100% response rate. Investigators submitted applications a median of 58 days (interquartile range [IQR], 40-83) after receipt of the protocol, and IRB approval took an additional 38 days (IQR, 26-62). Although eight applications were approved with little or no changes, IRBs requested an average of 3.5 changes per site. Changes involved study logistics and supervision for 45%, the research process for 43%, and the consent form for 91%. Despite these numerous requests, all eventually approved the basic protocol, including inclusion criteria, intervention, and data collection. Conclusions: The IRBs showed extreme variability in their initial responses to a standard protocol, but ultimately all gave approval. Almost all IRBs changed the consent form. A national, multicenter IRB process might streamline ethical review and warrants further consideration.