diff --git a/m4/hdf5.m4 b/m4/hdf5.m4
index d12b1b35f4b6b82e5bd1b16d18129392d261b929..fe6f393f41c40331148e7002e140192067c888cd 100644
--- a/m4/hdf5.m4
+++ b/m4/hdf5.m4
@@ -65,7 +65,7 @@ AC_DEFUN([DUNE_PATH_HDF5],[
 
  CPPFLAGS="$CPPFLAGS $_dune_hdf5_incpath"
 
- HDF5_CPPFLAGS=""
+ HDF5_CPPFLAGS="$_dune_hdf5_incpath"
  HDF5_LDFLAGS=""
  HDF5_LIBS=""
  HDF5_PARALLEL=0