This is an R-Commander plug-in for the MAd package (Meta-Analysis with Mean Differences). This package enables the user to conduct a meta-analysis in a menu-driven, graphical user interface environment (e.g., SPSS), while having the full statistical capabilities of R and the MAd package. The MAd package itself contains a variety of useful functions for conducting a research synthesis with mean differences data. One of the unique features of the MAd package is in its integration of user-friendly functions to complete many of the statistical steps involved in a meta-analysis with mean differences. It uses recommended procedures as described in The Handbook of Research Synthesis and Meta-Analysis (Cooper, Hedges, & Valentine, 2009).