This chapter examines how memory function enables agency and how memory dysfunction disables agency. Because some memory systems mediating goal-directed behavior may be intact while others are dysfunctional, neurological and psychiatric disorders that impair some of these systems can impair agency to varying degrees. The chapter also analyzes the role of memory in personal identity. Updating the content of episodic memories is necessary to adapt to the environment. But adaptability may come at the expense of identity over an extended period. The chapter discusses precedent autonomy in dementia. It discusses whether the ethical and legal force of an advance directive about medical care in a demented state holds from the time when a person is competent to a time when she is no longer competent and no longer the same person.