The purpose of this longitudinal study was to examine word-reading ability of subjects with probable Alzheimer's disease (AD), using the National Adult Reading Test (NART). In addition to the NART, a battery of neuropsychological tests was administered to 18 AD and 20 elderly control subjects at yearly intervals over 3 years. Repeated measures analysis with grouping factors showed that the controls scored better than AD subjects on the NART at each test date and the AD subjects scored significantly worse over time. NART scores were significantly correlated with dementia severity in AD subjects at final testing only, suggesting that the NART is sensitive to dementia severity only at the later stages of the disease. Associations between the NART and other cognitive measures yielded few significant results. Finally, error responses to NART words were summarized by type and percentage for each group at each test session.