There is a widespread consensus about the need for accreditation systems for evaluating post-graduate medical education programs, but accreditation systems differ substantially across countries. A cross-country comparison of accreditation systems could provide valuable input into policy development processes. We reviewed the accreditation systems of five countries: The United States, Canada, The United Kingdom, Germany and Israel. We used three information sources: a literature review, an online search for published information and applications to some accreditation authorities. We used template analysis for coding and identification of major themes. All five systems accredit according to standards, and basically apply the same accreditation tools: site-visits, annual data collection and self-evaluations. Differences were found in format of standards and specifications, the application of tools and accreditation consequences. Over a 20-year period, the review identified a three-phased process of evolution--from a process-based accreditation system, through an adaptation phase, until the employment of an outcome-based accreditation system. Based on the five-system comparison, we recommend that accrediting authorities: broaden the consequences scale; reconsider the site-visit policy; use multiple data sources; learn from other countries' experiences with the move to an outcome-based system and take the division of roles into account.