This paper presents a single-case study of the speech production performance of an aphasic subject, CJ. CJ's productions included a large number of perseverations. Perseverated responses comprised real words, nonwords, and subword segments and the majority of them were unrelated to the target items (either by sound or meaning). An analysis of the determinants of perseverate responding revealed that the frequency of the target name was an important factor. Moreover, there appeared to be both a semantic and a phonological basis for perseveration. These results are used to evaluate a recent account of perseveration.