diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index be3beb1..38715b8 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -27,7 +27,7 @@ jobs:
     # install dependencies
     - name: Install boost & help2man for Linux
       if: matrix.os == 'ubuntu-20.04'
-      run: sudo apt-get update && sudo apt-get install -yq libboost-dev libboost-serialization-dev libboost-program-options-dev help2man libgmp-dev
+      run: sudo apt-get update && sudo apt-get install -yq libboost-dev libboost-serialization-dev libboost-program-options-dev help2man libgmp-dev libmpfr-dev
       
     - name: Install gmp for Mac
       if: matrix.os == 'macos-13'