The present investigation explores the hypothesis that lexical information influences performance on nonword repetition tasks. The subjects – 30 normally achieving, school-aged boys – repeated multisyllabic nonword pairs, constructed to vary only in the lexicality of their constituent stressed syllables. Nonwords with stressed syllables corresponding to real words were repeated significantly more accurately than nonwords with non-lexical stressed syllables; stressed syllable lexicality primarily influenced repetition of the remaining unstressed syllables. Subsequent analyses revealed that the overwhelming majority of repetition errors operated to transform non-lexical sequences into real words, even when doing so violated both strong acoustic cues and articulatory ease. We conclude that lexical long-term memory information intrudes on nonword repetition performance, including stimuli that are within the limits of immediate memory span. These results suggest a number of caveats concerning the construction and interpretation of nonword repetition tasks and raise questions about the role of such tasks in assessing phonological working memory.