diff --git a/ext/monitor/extconf.rb b/ext/monitor/extconf.rb
new file mode 100644
index 0000000..5b4a0e2
--- /dev/null
+++ b/ext/monitor/extconf.rb
@@ -0,0 +1,4 @@
+require 'mkmf'
+target = "monitor_mixin"
+
+create_makefile(target)
diff --git a/ext/monitor/monitor_mixin.c b/ext/monitor/monitor_mixin.c
new file mode 100644
index 0000000..0f3ecc3
--- /dev/null
+++ b/ext/monitor/monitor_mixin.c
@@ -0,0 +1,111 @@
+/**********************************************************************
+
+  monitor_mixin.c -
+
+  $Author: Brian Gugliemetti $
+  created at: Wed Apr 27 14:51:06 CST 2011
+
+  All the files in this distribution are covered under the Ruby's
+  license (see the file COPYING).
+
+**********************************************************************/
+
+#include "ruby.h"
+
+static VALUE rb_mon_enter _((VALUE monitor));
+static VALUE rb_mon_exit _((VALUE monitor));
+static VALUE rb_mon_check_owner _((VALUE monitor));
+static VALUE rb_mon_synchronize _((VALUE monitor, VALUE (*func)(VALUE arg), VALUE arg));
+void Init_monitor_mixin _((void));
+
+VALUE rb_mMonitorMixin;
+
+/*
+ * MonitorMixin methods
+ */
+
+VALUE
+rb_mon_check_owner(VALUE monitor)
+{
+	VALUE mon_owner = rb_ivar_get(monitor, rb_intern("@mon_owner"));
+	VALUE th = rb_thread_current();
+	if (mon_owner != th)
+	{
+		rb_raise(rb_eThreadError, "current thread not owner");
+	}
+}
+
+/*
+ * call-seq:
+ *   monitor_mixin.mon_enter -> int
+ *
+ * Returns number of times the monitor has entered.
+ */
+
+VALUE
+rb_mon_enter(VALUE monitor)
+{
+	VALUE mon_owner = rb_ivar_get(monitor, rb_intern("@mon_owner"));
+	VALUE mon_mutex = rb_ivar_get(monitor, rb_intern("@mon_mutex"));
+	VALUE mon_count;
+	ID mon_count_id;
+
+	VALUE th = rb_thread_current();
+
+	if (mon_owner != th)
+	{
+		rb_mutex_lock(mon_mutex);
+		rb_ivar_set(monitor, rb_intern("@mon_owner"), th);
+	}
+	mon_count = rb_ivar_get(monitor, mon_count_id = rb_intern("@mon_count"));
+	rb_ivar_set(monitor, mon_count_id, mon_count = INT2NUM(NUM2INT(mon_count) + 1));
+	return mon_count;
+}
+
+VALUE
+rb_mon_exit_no_check(VALUE monitor)
+{
+	VALUE mon_count;
+	VALUE mon_mutex;
+	ID mon_count_id;
+
+	mon_count = rb_ivar_get(monitor, mon_count_id = rb_intern("@mon_count"));
+	rb_ivar_set(monitor, mon_count_id, mon_count = INT2NUM(NUM2INT(mon_count) - 1));
+	if(mon_count == INT2NUM(0))
+	{
+		rb_ivar_set(monitor, rb_intern("@mon_owner"), Qnil);
+		mon_mutex = rb_ivar_get(monitor, rb_intern("@mon_mutex"));
+		rb_mutex_unlock(mon_mutex);
+	}
+	return mon_count;
+}
+
+VALUE
+rb_mon_exit(VALUE monitor)
+{
+	rb_mon_check_owner(monitor);
+	return rb_mon_exit_no_check(monitor);
+}
+
+VALUE
+mon_synchronize(VALUE monitor, VALUE (*func)(VALUE arg), VALUE arg)
+{
+    rb_mon_enter(monitor);
+    return rb_ensure(func, arg, rb_mon_exit_no_check, monitor);
+}
+
+VALUE
+rb_mon_synchronize(VALUE monitor)
+{
+	return mon_synchronize(monitor, rb_yield, Qnil);
+}
+
+void
+Init_monitor_mixin()
+{
+	rb_mMonitorMixin = rb_define_module("MonitorMixin");
+    rb_define_method(rb_mMonitorMixin, "mon_check_owner", rb_mon_check_owner, 0);
+    rb_define_method(rb_mMonitorMixin, "mon_enter", rb_mon_enter, 0);
+    rb_define_method(rb_mMonitorMixin, "mon_exit", rb_mon_exit, 0);
+    rb_define_method(rb_mMonitorMixin, "mon_synchronize", rb_mon_synchronize, 0);
+}
diff --git a/lib/monitor.rb b/lib/monitor.rb
index d4bfb67..64c9f9f 100644
--- a/lib/monitor.rb
+++ b/lib/monitor.rb
@@ -43,6 +43,7 @@ empty_cond.signal.
 =end
 
 require 'thread'
+require 'monitor_mixin.so'
 
 #
 # Adds monitor functionality to an arbitrary object by mixing the module with
@@ -167,42 +168,6 @@ module MonitorMixin
   # For backward compatibility
   alias try_mon_enter mon_try_enter
 
-  #
-  # Enters exclusive section.
-  #
-  def mon_enter
-    if @mon_owner != Thread.current
-      @mon_mutex.lock
-      @mon_owner = Thread.current
-    end
-    @mon_count += 1
-  end
-
-  #
-  # Leaves exclusive section.
-  #
-  def mon_exit
-    mon_check_owner
-    @mon_count -=1
-    if @mon_count == 0
-      @mon_owner = nil
-      @mon_mutex.unlock
-    end
-  end
-
-  #
-  # Enters exclusive section and executes the block.  Leaves the exclusive
-  # section automatically when the block exits.  See example under
-  # +MonitorMixin+.
-  #
-  def mon_synchronize
-    mon_enter
-    begin
-      yield
-    ensure
-      mon_exit
-    end
-  end
   alias synchronize mon_synchronize
 
   #
@@ -226,12 +191,6 @@ module MonitorMixin
     @mon_mutex = Mutex.new
   end
 
-  def mon_check_owner
-    if @mon_owner != Thread.current
-      raise ThreadError, "current thread not owner"
-    end
-  end
-
   def mon_enter_for_cond(count)
     @mon_owner = Thread.current
     @mon_count = count