diff --git a/src/api.F90 b/src/api.F90
index b39a2f8fa..05d276015 100644
--- a/src/api.F90
+++ b/src/api.F90
@@ -29,6 +29,10 @@ module openmc_api
   use timer_header
   use volume_calc,     only: openmc_calculate_volumes
 
+#ifdef CAD
+  use cad_header,      only: free_memory_cad
+#endif
+  
   implicit none
 
   private
@@ -149,6 +153,7 @@ contains
     root_universe = -1
     run_CE = .true.
     run_mode = -1
+    dagmc = .false.
     satisfy_triggers = .false.
     call openmc_set_seed(DEFAULT_SEED)
     source_latest = .false.
@@ -325,7 +330,10 @@ contains
     call free_memory_tally_filter()
     call free_memory_tally_derivative()
     call free_memory_bank()
-
+#ifdef CAD
+    call free_memory_cad()
+#endif
+    
     ! Deallocate CMFD
     call deallocate_cmfd(cmfd)
 
diff --git a/src/cad.cpp b/src/cad.cpp
index 58eeeff48..325fda9de 100644
--- a/src/cad.cpp
+++ b/src/cad.cpp
@@ -42,7 +42,7 @@ void load_cad_geometry_c()
   return;
 }
 
-void dealloc_cad_c()
+void free_memory_cad_c()
 {
   delete DAGMC;
 }
diff --git a/src/cad.h b/src/cad.h
index c3dc49715..ff2540841 100644
--- a/src/cad.h
+++ b/src/cad.h
@@ -5,7 +5,9 @@
 #include "cell.h"
 #include "surface.h"
 
+extern moab::DagMC* DAGMC;
+
 extern "C" void load_cad_geometry_c();
-extern "C" void dealloc_cad_c();
+extern "C" void free_memory_cad_c();
 
 #endif // CAD_H
diff --git a/src/cad_header.F90 b/src/cad_header.F90
index 1fc6dbf16..3c53254c9 100644
--- a/src/cad_header.F90
+++ b/src/cad_header.F90
@@ -9,8 +9,8 @@ module cad_header
      subroutine load_cad_geometry_c() bind(C)
      end subroutine load_cad_geometry_c
 
-     subroutine dealloc_cad_c() bind(C)
-     end subroutine dealloc_cad_c
+     subroutine free_memory_cad_c() bind(C)
+     end subroutine free_memory_cad_c
 
   end interface
 
@@ -20,8 +20,8 @@ contains
     call load_cad_geometry_c()
   end subroutine load_cad_geometry
 
-  subroutine dealloc_cad()
-    call dealloc_cad_c()
-  end subroutine dealloc_cad
+  subroutine free_memory_cad()
+    call free_memory_cad_c()
+  end subroutine free_memory_cad
 
 end module cad_header
diff --git a/src/constants.F90 b/src/constants.F90
index a3118f84d..80c1d2322 100644
--- a/src/constants.F90
+++ b/src/constants.F90
@@ -429,7 +429,12 @@ module constants
        MODE_EIGENVALUE  = 2, & ! K eigenvalue mode
        MODE_PLOTTING    = 3, & ! Plotting mode
        MODE_PARTICLE    = 4, & ! Particle restart mode
+#ifdef CAD
+       MODE_VOLUME      = 5, & ! Volume calculation mode
+       MODE_CAD         = 6    ! CAD-based Geometry mode
+#else
        MODE_VOLUME      = 5    ! Volume calculation mode
+#endif
 
   ! Electron treatments
   integer, parameter :: &
diff --git a/src/input_xml.F90 b/src/input_xml.F90
index 7361dd85b..16c107d13 100644
--- a/src/input_xml.F90
+++ b/src/input_xml.F90
@@ -11,6 +11,7 @@ module input_xml
   use error,            only: fatal_error, warning, write_message, openmc_err_msg
   use geometry,         only: neighbor_lists
   use geometry_header
+  use cad_header
   use hdf5_interface
   use list_header,      only: ListChar, ListInt, ListReal
   use material_header
@@ -216,6 +217,17 @@ contains
     ! Get proper XMLNode type given pointer
     root % ptr = root_ptr
 
+    ! Check for use of CAD geometry
+    if (check_for_node(root, "dagmc")) then
+#ifdef CAD
+       call get_node_value_bool(root, "dagmc", dagmc)
+#else
+       if (dagmc) then
+          call fatal_error("CAD mode unsupported for this build of OpenMC")
+       end if
+#endif
+    end if
+
     if (run_mode == MODE_EIGENVALUE) then
       ! Preallocate space for keff and entropy by generation
       call k_generation % reserve(n_max_batches*gen_per_batch)
@@ -375,6 +387,12 @@ contains
     type(DictIntInt) :: cells_in_univ_dict ! Used to count how many cells each
                                            ! universe contains
 
+    if (dagmc) then
+       call write_message("Reading CAD geometry...", 5)
+       call load_cad_geometry()
+       return
+    end if
+
     ! Display output message
     call write_message("Reading geometry XML file...", 5)
 
diff --git a/src/settings.F90 b/src/settings.F90
index ec7bbf2c8..4efe25102 100644
--- a/src/settings.F90
+++ b/src/settings.F90
@@ -80,6 +80,9 @@ module settings
   ! Mode to run in (fixed source, eigenvalue, plotting, etc)
   integer(C_INT), bind(C) :: run_mode
 
+  ! flag for use of CAD geometry
+  logical, bind(C) :: dagmc = .false.
+  
   ! Restart run
   logical(C_BOOL), bind(C) :: restart_run
 
diff --git a/src/xml_interface.F90 b/src/xml_interface.F90
index 7aa86556b..39c6330ec 100644
--- a/src/xml_interface.F90
+++ b/src/xml_interface.F90
@@ -12,6 +12,7 @@ module xml_interface
   public :: check_for_node
   public :: get_node_list
   public :: get_node_value
+  public :: get_node_value_bool
   public :: get_node_array
   public :: node_value_string
   public :: node_word_count