In this study we tested the hypothesis that visual repetition priming for words depends upon the accessibility of lexical units in the visual input lexicon. For this purpose, we investigated a dyslexic patient, A.M., whose neuropsychological performances suggested an impaired access to the lexical route of reading. According to the predictions, Experiments 1 and 2 demonstrated deficient priming in tests involving the visual presentation of words (Word Identification and Stem Completion). In Experiment 3, we demonstrated that A.M.'s deficient priming was specific for visually presented words, in that the auditory presentation elicited a normal priming effect (auditory Stem Completion). These data are discussed in the light of a theoretical framework suggesting a fractionation of the modalities by which repetition priming can be elicited, each mediated by a particular memory subsystem.