To be more responsive to the nation's health needs, medical educators should identify those personal qualities associated with effective primary medical care. For this research Machiavellianism was chosen as a tracer character trait opposed to the characteristics embodied in an ideal family physician. A survey was conducted of 167 freshmen from one medical school and 823 seniors from four medical schools, with Machiavellianism scores used to predict their professional role characteristics, attributional style toward patients, and choice of a career specialty. Results showed that 15% of all students scored positively on the Machiavellianism scale. Mean Machiavellianism scores for seniors did not differ from those for freshmen. Men had higher Machiavellianism scores than women. Those students with high Machiavellianism scores relied excessively on high-tech medicine and were externally controlled, intolerant of ambiguity, and authoritarian. Seniors' high Machiavellianism scores predicted a negative attributional style toward geriatric and hypochondriac patients, thereby validating the use of Machiavellianism to measure medical students' indifference to patients and their problems.