We examined the contributions of phoneme-to-word facilitation and word-to-word inhibition to transposed-phoneme priming effects under unimodal and cross-modal presentations. Experiments 1A and 1B showed that the presentation of an auditory prime formed by transposing two phonemes in a given target word facilitated lexical decisions to auditory targets. This facilitation was independent of the lexicality of the primes. In Experiment 2 the targets were presented visually rather than auditorily. We found an inhibitory priming effect, which, in contrast to Experiment 1, was influenced by the lexicality of the primes, with an effect emerging only with word primes. These findings point to a greater impact of phoneme-to-word facilitation under unimodal presentation and a greater role for word-to-word inhibition under cross-modal presentation. Hence, by simply manipulating the modality of target presentation, it is possible to separately probe two central mechanisms postulated in models of spoken word recognition, namely phoneme-to-word activation and lexical competition.