diff --git a/IO/IOSS/vtkIOSSUtilities.cxx b/IO/IOSS/vtkIOSSUtilities.cxx
index 26470b965..bee76107a 100644
--- a/IO/IOSS/vtkIOSSUtilities.cxx
+++ b/IO/IOSS/vtkIOSSUtilities.cxx	
@@ -38,6 +38,7 @@
 #include <Ioss_NodeBlock.h>
 #include <Ioss_SideBlock.h>
 #include <Ioss_SideSet.h>
+#include <Iotr_Factory.h>
 
 #include <memory>
 
diff --git a/IO/IOSS/vtkIOSSReaderInternal.cxx b/IO/IOSS/vtkIOSSReaderInternal.cxx
index de8d456..237644b 100644
--- a/IO/IOSS/vtkIOSSReaderInternal.cxx
+++ b/IO/IOSS/vtkIOSSReaderInternal.cxx
@@ -9,6 +9,8 @@
 #include "vtkIOSSReaderCommunication.h"
 #include "vtkIOSSUtilities.h"
 
+#include VTK_IOSS(Iotr_Factory.h)
+
 #include "vtkCellArrayIterator.h"
 #include "vtkCellData.h"
 #include "vtkDataArraySelection.h"