High-reliability organizations, including high-reliability perinatal units, are built on a solid foundation of timely communication and collegial teamwork to maintain patient safety as a top priority. In these units, concise, real-time, and constant communication is valued. Teamwork and collegiality characterize the professional relationships and hierarchy is minimized. The Perinatal Patient Safety Project utilized human factors techniques and systems improvements to create high-reliability perinatal units within a 1-year pilot project. This article focuses on the approaches used to improve communication in 4 Kaiser Permanente medical centers participating in this project.