Modernsoftwaresystemsincreasinglyusecommercial-o?-the-shelf(COTS)so- ware products as building blocks. In some cases, major software systems are assembled with virtually no custom code in the system. The use of COTS software products as components o?ers the promise of rapid delivery to end users, shared development costs with other customers, and an opportunity for expanding mission or business capabilities and performance as improvements are made in the commercial marketplace. Few organizations today can a?ord the resources and time to replicate market-tested capabilities. Yet, the promise of COTS products is too often not realized in practice. There have been more failures than successes in using COTS software products. The research and software practitioner communities have been working with COTS-based software systems for a number of years. There is now su?cient documented experience in the community to collect, analyze, and disseminate success stories, common failings, lessons-learned, and research advances. The mounting experience shows that the e?ective use of COTS software products in major software systems demands new skills, knowledge, and abilities, changed roles and responsibilities, and di?erent techniques and processes. The International Conference on COTS-Based Software Systems (ICCBSS) focuses on the challenges of building and maintaining systems that incorporate COTSsoftwareproducts.Theconferencesponsors, the National Research Co- cil Canada, the Software Engineering Institute, and the University of Southern California Center for Software Engineering, aim to bring together managers, – velopers, maintainers, and researchers to share their expertise and experience.