An unexpected dissociation between intact propositional speech and impaired language comprehension was observed in a right handed patient following a right hemisphere stroke. Although CHO's comprehension was intact at the single word level, his ability to comprehend a wide range of sentence structures was profoundly impaired. This deficit was observed in the context of normal sentence production both with regard to semantic and syntactic content. This case provides further evidence for the independence of on-line language input and output systems.