The goal of this study is the analysis of a set of open-source electronic health record (EHR) systems to determine if their functionalities are accordantly to ISO standards for EHRs systems architectures. This study describes the follow-up of five EHR systems previously analyzed in 2008. For this analysis, ISO standards have been used as a guide to determine the referenced architecture and features of a standardized electronic health records system, as well as the environmental context for which the software has been built. The five open source EHR systems were selected and evaluated according to a two-dimensional criterion based on functional requirements set out in the ISO/TS 18308:2004 standard and contextual requirements established by the ISO/TR 20514:2005 standard. The final results have shown that, in general, the analyzed software had included a number of additional featured described by both standards. Nevertheless, there are several requirements that have not yet been included, mainly at the level of fully functional and provider enterprise levels. © 2013 IEEE.