The present study investigated whether neural structures become less functionally differentiated and specialized with age. We studied ventral visual cortex, an area of the brain that responds selectively to visual categories (faces, places, and words) in young adults, and that shows little atrophy with age. Functional MRI was used to estimate neural activity in this cortical area, while young and old adults viewed faces, houses, pseudowords, and chairs. The results demonstrated significantly less neural specialization for these stimulus categories in older adults across a range of analyses. There is growing behavioral evidence that the functional architecture of cognition becomes dedifferentiated with age: A number of studies have found that correlations among distinct measures of cognitive function are more intercorrelated in older subjects than in younger adult subjects (1-5). Furthermore, markers of central sensory function (e.g., corrected visual and auditory acuity) account for virtually all age-related variance on a broad array of higher-order cognitive tasks, including speed of processing, memory, verbal fluency, and reasoning (4, 6). Based on these and related findings, Baltes and Lindenberger (6) argued that aging reduces the degree to which behavior is specialized (or differentiated) for individual tasks and that a domain-independent decline in neural integrity is the mechanism underlying this dedifferentiation. Providing a more specific mechanism for dedifferentiation, Li et al. (7) have argued that both empirical and computational data suggest that increased age results in a decrease in distinctiveness of neural representations due to deficient dopaminergic modulation. With the advent of neuroimaging techniques, the dedifferentiation hypothesis can be addressed more directly than is possible with behavioral techniques alone. Thus, in the present study, we test whether neural structures become dedifferentiated with age, by examining the degree of category-specificity that is present in ventral visual cortex in young and old adults.