A package for performing Mendelian randomization using GWAS summary data. It uses the IEU GWAS database to obtain data automatically, and a wide range of methods to run the analysis. You can use the MR-Base web app to try out a limited range of the functionality in this package, but for any serious work we strongly recommend using this R package.

January 2020 major update

We have made substantial changes to the package, database and reference panels. For full details of the changes, please visit https://mrcieu.github.io/TwoSampleMR/articles/gwas2020.html


To install the latest version of TwoSampleMR, perform as normal:


To update the package just run the install_github("MRCIEU/TwoSampleMR") command again.

We recommend using this new version going forwards but for a limited time we are enabling backwards compatibility, in case you are in the middle of analysis or need to reproduce old analysis. In order to use the legacy version of the package and the database, install using:



A docker image containing R with the TwoSampleMR package pre-installed is available here: https://hub.docker.com/r/mrcieu/twosamplemr