diff --git a/CHANGES.txt b/CHANGES.txt
index 133b4c3..d42144f 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -3,6 +3,9 @@ Next Release
   - When using the monitor, the nonblocking character input at
     $F004 should now work on the Microsoft Windows platform.
 
+  - Fixed that relative branch calculations would not use the correct 
+    start address when assembling in the monitor.  Closes #10.
+
 0.6 (2009-08-11)
 
   - Added monitor shortcut "a" for "assemble".
diff --git a/src/py65/monitor.py b/src/py65/monitor.py
index 6e68568..5c1f74c 100644
--- a/src/py65/monitor.py
+++ b/src/py65/monitor.py
@@ -173,7 +173,7 @@ class Monitor(cmd.Cmd):
             self._output("Bad label: %s" % start)
             return
 
-        bytes = self._assembler.assemble(statement)
+        bytes = self._assembler.assemble(statement, start)
         if bytes is None:
             self._output("Assemble failed: %s" % statement)
         else:
diff --git a/src/py65/tests/test_monitor.py b/src/py65/tests/test_monitor.py
index 0fe5c05..0e5eedf 100644
--- a/src/py65/tests/test_monitor.py
+++ b/src/py65/tests/test_monitor.py
@@ -59,6 +59,14 @@ class MonitorTests(unittest.TestCase):
         out = stdout.getvalue()
         self.assertEqual("Assemble failed: foo\n", out)
 
+    def test_do_assemble_passes_addr_for_relative_branch_calc(self):
+        stdout = StringIO()
+        mon = Monitor(stdout=stdout)
+        mon.do_assemble('4000 bvs $4005')
+
+        out = stdout.getvalue()
+        self.assertEqual("$4000  70 03     BVS $4005\n", out)
+
     def test_help_assemble(self):
         stdout = StringIO()
         mon = Monitor(stdout=stdout)