This chapter outlines the changes in cognition that occur in normal human aging, in an effort to provide a backdrop against which neural changes can be interpreted. It highlights the cognitive domains that show the greatest declines with age and are also the most variable. The chapter reviews some of the evidence for age-related impairments in basic cognitive functions, focuses on attention and memory, and discusses briefly the attentional and memory processes that show relative preservation with age. Working memory is a multidimensional cognitive construct that has been hypothesized as the fundamental source of age-related deficits in a variety of cognitive tasks, including long-term memory, language, problem solving, and decision making. Theories of age-related decline in working memory generally assume some reduction in processing resources. Older adults exhibit significant deficits in tasks that involve active manipulation, reorganization, or integration of the contents of working memory. The cognitive domain that has probably received the most attention in normal aging is memory.