In the present article the requirements for waivers of informed consent in clinical research on subjects who are patients in a hospital are reviewed. The most important requirements seem to be that the research must pose minimal risk and obtaining informed consent is impracticable. It is suggested that requirements for waivers of consent in research ethics guidelines be modified to exclude the requirement of impracticable consent, but to retain that of minimal risk research, and to add another requirement that restricts modifications of the medical management procedures to those which are minor in some sense. According to these suggestions, waivers of consent for retrospective chart reviews are seen to be coherent
and consistent. These suggestions also imply that certain types of prospective observational studies should also be granted waivers of consent. On the other hand, waivers of consent should probably not be granted to any type of randomized clinical trials.

Keywords: Waiver of consent, Clinical, Observational research