The authors used data from the National Ambulatory Medical Care Survey from 1992 to 1999 on 3,198 office visits to explore the extent to which psychiatrists provide clinical preventive medical services to patients with severe mental illness. Preventive services were provided during 11 percent of the visits. A multivariate analysis showed that preventive services were more likely to have been provided for patients with a chronic medical condition, for patients who were also seen by a nurse or other health provider during the visit, in rural areas, and during longer visits. Preventive services were less likely to have been provided during visits to health maintenance organizations and visits that took place later in the study period.