The present study explored the role of so-called encapsulated knowledge in diagnosing clinical cases outside the expert physicians' domain of expertise. Neurologists and 2nd-year and 6th-year medical students were required to diagnose, recall, and explain the signs and symptoms of two cardiological and two pulmonological clinical case descriptions. Our experiment showed that neurologists diagnosed these clinical cases faster and more accurately than 2nd-year and 6th-year medical students. An inverted U-shaped relationship with levels of expertise was found in recall and pathophysiological protocols: 6th-year medical students remembered more information from the cases and produced more elaborated explanations for the described signs and symptoms than both other groups. The proportion of encapsulating concepts in recall and pathophysiological explanations, on the other hand, increased with levels of expertise. This pattern is similar to that found in previous studies on clinical case representations using only cases within the expert physicians' domain of expertise. Therefore, these results suggest that expert physicians process clinical case descriptions both within and outside their domain of expertise in essentially the same way. Copyright 2000 Academic Press.