diff --git a/Generators/AtlasHepMC/CMakeLists.txt b/Generators/AtlasHepMC/CMakeLists.txt
index 4a50fb1e304f35914bd39bfafeedef65aceee0b3..f3e29e5291e4635de0f38b920b345ea3ea8c318b 100644
--- a/Generators/AtlasHepMC/CMakeLists.txt
+++ b/Generators/AtlasHepMC/CMakeLists.txt
@@ -4,6 +4,7 @@ atlas_subdir( AtlasHepMC )
 
 # External(s) needed by the package.
 find_package( HepMC COMPONENTS HepMC HepMCfio )
+find_package( hepmc3 COMPONENTS HepMC3 HepMC3search )
 
 if (HEPMC3_USE)
 # Component(s) in the package.