The humanistic training of medical students is currently an important educational objective in medical schools. Part of this training is provided through disciplines within the humanities, but a large proportion comes through learning achieved within the cultural environment and interpersonal relationships of the medical school, especially from the teacher-student relationship. With the aim of studying the teacher-student relationship at a typical medical school in the state of São Paulo, Brazil, this case study was designed. Through ethnographic observations and in-depth interviews, in contrast with official teaching documents, we obtained data that were analyzed using a hermeneutic method, within analytical categories that were constructed from the theoretical reference framework for research and the empirical findings relating to the types of pedagogical relationships observed in this school. We constructed three types of relationship of this nature, based on: omnipotence of the teacher, construction of a link and disqualification of the student. In each of these, one predominant mode of behavior was being taught informally, thereby coming closer towards or moving away from the teaching of ethics and relational competence. Teacher-student relationships within medical schools need to be studied further, with clear definition of an institutional ethical standard for everyone, so that the objective of humanistic training within medicine can be achieved.