The issue of ethics in medical research grew in importance at the end of World War II, after the Nuremberg Code. In this period, some cases in the United States had demonstrated the need for the establishment of rules and procedures in medical research. In this article, the authors discuss some ethical concepts and their philosophical basis, stressing aspects related to research. Ethics in medical research is based upon three items: peer approaches, subject informed consent, and confidentiality of individual obtained data. The authors also summarize the Brazilian laws and directives to follow the precepts and to control the process of ethical issues in research with human participants. Finally, they approach practical questions of the Informed Consent Form as a consequence of their experiences analyzing more than one thousand research projects per year as members of the Internal Review Board of the University of São Paulo School of Medicine, São Paulo, Brazil.