Professional attitudes of 302 medical students in two pre-clerkship classes (years three and four) were measured. The aim was to assess changes in attitudes during and after a practical course in doctor-patient communication within a biomedically oriented curriculum. Attitudes were measured by means of a questionnaire containing three subscales: the Doctor-Patient Scale measuring patient-centredness, the Social Context Scale for psychosocial orientation and the Ideal Physician Scale for care orientation. The design of the study consisted of a pre-, post- and follow-up test with parallel versions of the questionnaire. Attitudes of female students were more patient-, psycho-social- and care-oriented (i.e. more humane) than those of their male counterparts. No changes in attitudes were found at the end of the communication course in either year three or year four. The course seemed to have less influence on attitudes than expected. Contrary to expectation, no erosion of attitude into a less humane direction was measured half a year later. Generally, students' attitudes seemed to be stable. Considerable educational effort seems to be needed to bring about a measurable change in attitudes.