To determine physician use of the Minimum Data Set (MDS), part of the Resident Assessment Instrument (RAI). A population-based survey. The United States A total of 2223 physicians listing geriatrics as their primary specialty, 1921 of whom are internists and 302 family physicians. A 34-item questionnaire asking nine physician-specific demographic questions; nursing home caseload; percent time spent reviewing MDS and care plan; how the information on the MDS was used. Physicians were also asked to describe their attitudes about the MDS. Among the 472 physicians who completed the survey and cared for nursing home patients, 357 were internists and 107 were family physicians. Ninety-one percent of the physicians were board certified, 76% had certificate of added qualifications in geriatrics, and 65% oversaw 20 nursing home patients. Only 11% of physicians reported reviewing the entire MDS, and 21% part of the MDS for all of their patients. Nineteen percent of physicians did not review the care plan for any of their patients. Fifty-six percent of 461 comments made by physicians regarding the MDS were negative or derogatory. Many practicing geriatricians are not using MDS to facilitate medical decisions. If this physician population is not using the MDS, there is a need to improve the information transfer from the MDS form to the busy clinician.