Recent developments in biomedical informatics research have afforded possibilities for great advances in health care delivery. As in most domains, there is a gulf between technologic artifacts and end users, which compromises the culture of safety in the workplace. This necessitates a broadening of disciplinary boundaries to consider cognitive and social factors related to the design and use of technology. The authors argue for a place of prominence for cognitive science in understanding nursing factors associated with patient safety. Cognitive science provides a framework for the analysis and modeling of complex human performance. Studies of clinical cognition can meaningfully inform and shape design, development, and assessment of information systems. Furthermore, they have a decisive impact on whether information technology has a positive influence on human performance and are especially important in understanding and promoting safe practices. These issues are discussed in the context of clinical informatics with a focus on nursing practice.