Biomedical research still does not have clear, written, agreed-upon underlying values (for a number of possible reasons that are discussed), and a variety of new pressures are making it necessary to formulate such principles. Toward that goal, this essay first traces the development of the underlying principles that have been formulated in the sphere of human subjects research, from the ancient Hippocratic injunction of do no harm to the three principles identified in 1979 by the National Commission for Protection of Human Subjects of Biomedical and Behavioral Research: respect for persons; beneficence; and justice. Using these principles as a pattern, the following "candidate principles" are proposed for biomedical research to stimulate discussion and the development of consensus among biomedical scientists: honesty of scientists (which encompasses the essential values of integrity, objectivity, verifiability, and truthfulness); respect for others (including respect for research subjects--both humans and other animals--colleagues, and the environment); scholarly competence (which is related to the processes of obtaining and passing on knowledge); and stewardship of resources (involving obligations to protect society from the problems intertwined with scientific advances). Guiding principles of this type must be articulated so they can be transmitted to upcoming scientists, who then can productively and responsibly help shape the future of the research enterprise.