Declines in object recognition are widely reported in older humans and animal models, but the exact nature of these deficits remains a topic of debate. Accumulating data over the past several years have implicated the perirhinal cortex of the medial temporal lobe as a structure that is particularly vulnerable to dysfunction in advancing age. Because the perirhinal cortex is critical for stimulus recognition, these data could explain recognition deficits. Reports of perirhinal cortical dysfunctions, however, stand in contrast to other notions that the perirhinal cortex is unaffected by old age and perhaps compensates for a compromised hippocampus. One source of these discrepant interpretations is the differing views regarding the contributions of perirhinal cortical computations to cognitive function, which span from complex sensory representations to novelty detection. In this chapter we will discuss recent data from humans and animal models regarding age-related declines in object recognition in relation to perirhinal cortical function, and we propose that the perirhinal cortex is critical for stimulus discrimination, a process that is a core feature of recognition.