The present study investigated the influence of medical expertise, case typicality, and illness script component (enabling conditions vs. consequences) on the speed of case information processing and subjective disease probabilities. It was hypothesized that expert subjects would process case information faster than nonexpert subjects, that typical information would be processed faster than atypical information, and that an interaction would be found between expertise level, typicality, and illness script: Experts were expected to be sensitive to typicality of both illness script components, while advanced students would be sensitive only to typicality of consequences. This sensitivity would also be reflected in assigned probability estimates. The data supported the predictions concerning the effects of expertise level and typicality; it was also found that expert physicians are particularly sensitive to a combination of prototypical enabling conditions and prototypical consequences. Implications of these results for the illness script theory are discussed.