Background: The offer of aggregate study results to research participants following study completion is increasingly accepted as a means of demonstrating greater respect for participants. The attitudes of research ethics board chairs towards this practice, although integral to policy development, are unknown.Objectives: To determine the attitudes of REB chairs and the practices of REBs with respect to disclosure of results to research participants.Design: A postal questionnaire was distributed to the chairs of English-language university-based REBs in Canada. In total, 88 REB (...) chairs were eligible. The questionnaire examined respondents’ attitudes towards offering participants completed study results, methods for delivering this information, and barriers to disclosing results.Findings: The response rate was 89.8%. Chairs were highly supportive of offering results to research participants. Only 19.5% of chairs responded that a policy or guideline that governed the return of research results to participants existed at their institution. Most chairs supported the idea of their REB instituting a set of guidelines recommending that researchers offer results to participants in a lay format. Chairs identified the major impediments to the implementation of programmes offering to return results to participants as being financial cost and retaining contact with research participants .Conclusions: University-based REB chairs overwhelmingly support the offer of research results to participants. This is incongruent with the frequent lack of existing REB guidelines recommending this practice. REBs should support guidelines that diminish identified barriers and promote consistency in offering to return results. (shrink)