There is some evidence that semantics, conceptual features, and phonology interact with syntactic processing of words; however, other accounts suggest that in particular, irregular and regular English nouns and verbs, which differ in their phonology, are processed through different routes. The processing of regular and irregular nouns, and of pseudoplurals (nouns with the phonological form of a plural that are morphologically singular, such as cheese), was examined in a final-word sentence priming task. When the noun itself was repeated by participants in a grammatical or ungrammatical context (We saw one/three dog/dogs) regulars and irregular singulars showed a straightforward grammaticality effect, with repetition faster in grammatical sentences, while pseudoplurals and irregular plurals showed no grammaticality effect. When a verb following the noun was repeated in a grammatical or ungrammatical context (The dog/dogs runs/run) an interaction was found between number and grammaticality: both regular and irregular singulars showed a grammaticality effect, while regular and irregular plurals showed no or a reverse grammaticality effect; this was true both of university students and older participants. Pseudoplurals showed a straightforward grammaticality effect in the direction predicted by their morphology. It is concluded that the processing of nouns with conflicting morphology and phonology – such as irregular plurals and pseudoplurals – is influenced by both these features. However, previous studies (Bock & Eberhard, 1993) that have found irregular plurals and pseudoplurals do not differ from regulars in their processing may have been affected by aspects of the tasks or stimuli chosen.