A survey of McMaster University's first six medical classes (1972-1977) has shown that neither completion of the science courses that are usually required for admission to other medical schools nor achievement of high grades in premedical studies has an important impact on graduates' perceptions of the medical curriculum or on their evaluation of their preparation for the first year of postgraduate training in comparison to other trainees. No influence of either premedical science background or grade point average was detected on career choices in relation to field of medicine entered, level of specialization, location and type of practice, or on factors influencing these choices.