Background: The Declaration of Helsinki prohibits the publication of articles that do not meet defined ethical standards for reporting of research ethics board approval and informed consent. Despite this prohibition and a call to highlight the deficiency for the reader, articles with potential ethical shortcomings continue to be published.Objective: To determine what proportion of articles in major medical journals lack statements confirming REB approval and informed consent, and whether accompanying commentary alerts readers to this deficiency.Design: Retrospective, observational study.Setting: Online review (...) of five major medical journals.Population: All clinical research articles published online between 1 January 2005 and 31 December 2006 in the BMJ, Lancet, Annals of Internal Medicine, JAMA and the New England Journal of Medicine.Measurements: Statement of REB approval and informed consent.Results: Of 1780 articles reviewed, 1133 met inclusion criteria , 36 articles lacked a statement of REB approval, 62 lacked disclosure of informed consent and 15 articles lacked both. Articles that did not state REB approval were associated with not stating informed consent . There were no editorial comments to alert readers to the lack of either REB approval or informed consent statements associated with any of the deficient articles.Conclusions: Articles that lack explicit statements of REB approval and informed consent are infrequent but continue to be published in major medical journals without editorial statements to alert the reader to this deficiency. (shrink)