diff --git a/CMakeLists.txt b/CMakeLists.txt
index aa093b5ef880f92bad4d47fc6837d978b0fb2e2b..583db0171579feb09b5a9d52a87bd9fffc31d9b3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -131,6 +131,7 @@ add_subdirectory(DDRec)
 add_subdirectory(DDDetectors)
 add_subdirectory(DDCond)
 add_subdirectory(DDAlign)
+add_subdirectory(DDDigi)
 if ( DD4HEP_USE_GEANT4 )
   if(Geant4_builtin_clhep_FOUND)
     set(CLHEP "")