diff --git a/src/mzscheme/gc2/newgc.c b/src/mzscheme/gc2/newgc.c
index 5c2392399c..94d0565cad 100644
--- a/src/mzscheme/gc2/newgc.c
+++ b/src/mzscheme/gc2/newgc.c
@@ -1528,12 +1528,27 @@ void GC_construct_child_gc() {
     newgc->primoridal_gc = MASTERGC;
 }
 
+static inline void save_globals_to_gc(NewGC *gc) {
+  gc->saved_mark_stack              = mark_stack;
+  gc->saved_GC_variable_stack       = GC_variable_stack;
+  gc->saved_GC_gen0_alloc_page_ptr  = GC_gen0_alloc_page_ptr;
+  gc->saved_GC_gen0_alloc_page_end  = GC_gen0_alloc_page_end;
+}
+
+static inline void restore_globals_from_gc(NewGC *gc) {
+  mark_stack              = gc->saved_mark_stack;
+  GC_variable_stack       = gc->saved_GC_variable_stack;
+  GC_gen0_alloc_page_ptr  = gc->saved_GC_gen0_alloc_page_ptr;
+  GC_gen0_alloc_page_end  = gc->saved_GC_gen0_alloc_page_end;
+}
+
 void GC_switch_out_master_gc() {
   static int initialized = 0;
 
   if(!initialized) {
     initialized = 1;
     MASTERGC = GC_get_GC();
+    save_globals_to_gc(MASTERGC);
     GC_construct_child_gc();
   }
   else {
@@ -1544,9 +1559,9 @@ void GC_switch_out_master_gc() {
 
 void GC_switch_in_master_gc() {
   GC_set_GC(MASTERGC);
+  restore_globals_from_gc(MASTERGC);
 }
 
-
 void GC_gcollect(void)
 {
   NewGC *gc = GC_get_GC();
diff --git a/src/mzscheme/gc2/newgc.h b/src/mzscheme/gc2/newgc.h
index 38c49ca61a..0c33f0bd18 100644
--- a/src/mzscheme/gc2/newgc.h
+++ b/src/mzscheme/gc2/newgc.h
@@ -147,8 +147,6 @@ typedef struct NewGC {
   AccountHook *hooks;
 
 
-
-
   unsigned long number_of_gc_runs;
   unsigned int since_last_full;
   unsigned long last_full_mem_use;
@@ -157,6 +155,13 @@ typedef struct NewGC {
   unsigned long peak_memory_use;
   unsigned long num_minor_collects;
   unsigned long num_major_collects;
+  
+  /* THREAD_LOCAL variables that need to be saved off */
+  MarkSegment *saved_mark_stack;
+  void *saved_GC_variable_stack;
+  unsigned long saved_GC_gen0_alloc_page_ptr;
+  unsigned long saved_GC_gen0_alloc_page_end;
+
 
   /* Callbacks */
   void (*GC_collect_start_callback)(void);