The purpose of this study was to identify the nature of the deficit for a conduction aphasic patient in order to evaluate two different theories of conduction aphasia. First, a conduction aphasic patient FS was tested on auditory word-pair discrimination, word-repetition, and picture-naming. The results of these tasks indicated that her deficit was likely to be post-lexical rather than perceptual or lexical. Next, we examined her repetition performance for two types of nonwords (high-wordlike and low-wordlike nonwords) to distinguish the two theories. FS exhibited a wordlikeness effect: she produced more correct moras and more correct combinations of moras for high-wordlike nonwords than low-wordlike nonwords. We conclude that she had difficulty in maintaining stable phonological representations of verbal materials in the output buffer. © 2002 Elsevier Science (USA). All rights reserved.