Of 1,500 medical students at four medical schools, 1,053 anonymously and voluntarily completed questionnaires eliciting information on their knowledge and attitudes toward the Medicare program. Their responses indicate that 80% of them have little or no knowledge regarding the details of the program. Despite this lack of information, a large majority of the students have opinions which are, in general, negative. The attitudes and opinions expressed were remarkably homogeneous in each of the four classes at each school. There were differences between the schools which may depend upon the ecology of the school, ie, socioeconomic background of students and types of careers pursued by the graduates. On the basis of data available, it would seem that a significant proportion of medical students believe that their career plans have been altered by this legislation. This ranges from a high of 24.6% in the fourth-year class of school C to a low of 3.5% of the first-year class in school B.