Investigators searched Medline and HealthSTAR databases from January 1, 1985 through June 30, 1999 to identify articles on suboptimal prescribing in those age 65 years and older. A manual search of the reference lists from identified articles and the authors' article files, book chapters, and recent reviews was conducted to identify additional articles. The definitions for various types of suboptimal prescribing (polypharmacy, inappropriate, and underutilization) are numerous, and measurement varies from study to study. The literature suggests that suboptimal prescribing is common in older outpatients and inpatients. Moreover, there is significant morbidity and mortality associated with suboptimal prescribing for these older patients. Evidence from well-controlled studies suggests that multidisciplinary teams and clinical pharmacy interventions can modify suboptimal drug use in older people. Future research is necessary to measure and test other methods for tackling this major public health problem facing older people.