A cross-modality priming paradigm was used to examine the contribution of conceptual processing operations to performance on a word stem-completion task. Patients with Alzheimer's disease (AD), healthy elderly controls, and healthy young controls, studied words presented under two conditions, (1) visually and (2) orally, and were subsequently tested using a visual stem-completion task. AD patients were impaired relative to controls on stem completion. All groups showed a significant within-modality priming effect (visual study/visual test) but no significant cross-modal effect (auditory study/visual test), the latter taken to indicate a lack of a conceptual component in the stem-completion task. The results are discussed in relation to theories of priming deficits in AD patients.