In contrast to the results of many previous studies, Colombo (1986) has demonstrated that form related priming is sometimes inhibitory. Colombo proposed that inhibition reflects the suppression of lexical items orthographically related to the prime. We suggest, however, that form-related inhibition arises as a result of competition between discrepant prime-target phonemes. During the phonological encoding of the target word, active phonemes from the prime might be mistakenly selected, causing a delay in responding. We present a connectionist model that implements this account, and simulates tiie empirical data. The model is supported by the results of an experiment that distinguishes between the lexical suppression and phonological competition views