The R package compareGroups provides functions meant to facilitate the construction of bivariate tables (descriptives of several variables for comparison between groups) and generates reports in several formats (LATEX, HTML or plain text CSV). Moreover, bivariate tables can be viewed directly on the R console in a nice format. A graphical user interface (GUI) has been implemented to build the bivariate tables more easily for those users who are not familiar with the R software. Some new functions and methods have been incorporated in the newest version of the compareGroups package (version 1.x) to deal with time-to-event variables, stratifying tables, merging several tables, and revising the statistical methods used. The GUI interface also has been improved, making it much easier and more intuitive to set the inputs for building the bivariate tables. The ?rst version (version 0.x) and this version were presented at the 2010 useR! conference (Sanz, Subirana, and Vila 2010) and the 2011 useR! conference (Sanz, Subirana, and Vila 2011), respectively. Package compareGroups is available from the Comprehensive R Archive Network at http://CRAN.R-project.org/package=compareGroups.