Because of the pharmacologic power of psychotropic medications, the potential for adverse effects, and the changing popularity of particular psychotropic drugs, it is vital for pharmacoepidemiologists to monitor the prescribing patterns of these medications. Using data from the 1985 National Ambulatory Medical Care Survey (NAMCS), this article assesses psychotropic medication prescribing by U.S. ambulatory care physicians. Psychotropic medications are classified into three categories: Minor tranquilizers (i.e., anxiolytics and sedative-hypnotics), antidepressants, and antipsychotics. The prescribing patterns of psychiatrists, primary care clinicians, and all other physicians are compared. Differences in psychotropic prescribing patterns by psychiatric diagnosis are examined as well. The excessive use of minor tranquilizers, the continuing use of first-generation psychotropic medications (particularly minor tranquilizers), and the lack of concordance between diagnoses and prescribed psychotropic medications are discussed. © 1991, SAGE Publications. All rights reserved.