Most theories of language recognize the importance and complexity of verbs. Verbs convey both semantic and syntactic information, and therefore, the study of verb representation and processing can provide important insights into the nature and relationship of semantic and syntactic representation within the language processing system. Two models of verb representation were examined: (1) Semantic Complexity (Johnson-Laird, 1983); and (2) Conceptual Constituents (Pinker, 1989). The validity of these models was investigated by examining patterns of verb disruption in seven language impaired individuals. Investigation of patients' verb processing did not provide evidence for a model of verb representation based on semantic complexity, however, it did provide support for semantic representation of thematic roles within the lexicon separate from syntactic representation as posited by the conceptual constituent model. These findings were followed by an experiment investigating whether the language processing system has a bias for particular thematic roles in specific syntactic positions. The results indicated no bias for the syntactic position of specific thematic roles.