This article examines the importance of case studies in urban planning. It explains that case studies are used to analyze urban behaviors in the political arena, in neighborhoods and in other places, and in providing exemplars of best practices in physical planning. The article describes the nature of case studies used in urban planning and the pattern of their application. An analysis of representative studies reveals several patterns, including an effort to develop cases that translate knowledge into action, that pay attention to place or the physical dimensions of a question, and that have a tendency to revisit and re-evaluate a phenomenon which has been studied at an earlier time.