A group of drugs that causes chemical castration, the luteinizing hormone releasing hormone (LHRH) analogs, has been implicated in cognitive deficits in people using these drugs. Controlled studies in women and case reports from male and female patients support the hypothesis that cognitive changes occur in many patients treated with these pharmaceutical agents. In this paper, actions of LHRH analogs, relationships between sex hormones and cognition, and cognitive effects of LHRH analogs are reviewed. Studies to date have focused on memory problems. Areas that require further research are the effects of LHRH analogs on cognitive functions other than memory, the effects in men, and cognitive effects of other treatments that affect sex hormone levels such as surgical castration.