To determine what factors distinguish medical students who choose primary care careers, 381 graduating medical students at eight New England medical schools were surveyed by questionnaire prior to the 1988 National Resident Matching Program. Students were asked to indicate the degrees of influence that various factors had on their specialty choices, using a Likert-type scale ranging from "totally unimportant" to "decisive." Compared with their peers who chose high-technology specialties, those who chose primary care were more likely to be motivated by the opportunities to provide direct patient care (p less than .001), care in an ambulatory setting (p less than .001), and continuity of care (p less than .001) and the opportunity to be involved in the psychosocial aspects of medical care (p less than .001). Those who chose high-technology specialties were more likely to be motivated by desires for a large income (p less than .001) and more prestige (p less than .005), and the opportunities for research (p less than .001), more regular hours (p less than .005), more leisure and family time (p less than .001), and a better call schedule as a resident (p less than .01). Neither student age, race, sex, marital status, and level of debt nor concern about the increasing regulation of medical practice, malpractice, health manpower reports, and the increasing numbers of elderly, chronically ill, and AIDS patients were found to be significant factors in the students' choice of primary care.