The Institute of Medicine (IOM) Committee on Ethical Considerations for Revisions to DHHS Regulations for Protection of Prisoners Involved in Research published its report in 2006. It was charged with developing an ethical framework for the conduct of research with prisoners and identifying the safeguards and conditions necessary to ensure that research with prisoners is conducted ethically. The recommendations contained in the IOM report differ from current European regulations in several ways, some being more restrictive and some less so. For example, the IOM report suggests limiting the percentage of prisoners that should be involved in a biomedical study to 50%, a limit that does not exist in Europe. However, the report does not specifically advise against research without a direct benefit to an individual prisoner: the European regulations are more restrictive than the IOM committee recommendations in this respect. The definition of minimal risk varies, as well as the proposed role of the minimal risk requirement and of the principle of subsidiarity (research that can only be done effectively in prisons). The IOM report proposes a number of thoughtful suggestions, which it would be beneficial to implement everywhere, such as registers of research on prisoners. The European regulations offer pragmatic solutions to several thorny issues. In summary, the IOM committee report represents an admirable effort to tackle the present inconsistencies and deficiencies of federal regulations in the US on research on prisoners (45 CFR 46 Subpart C). Nonetheless, before acting on the recommendations, US regulators might consider revisiting international guidelines such as those published by the Council for International Organizations of Medical Science (CIOMS) and the Declaration of Helsinki.