diff --git a/run_tests.sh b/run_tests.sh
index 3f00453..eaa7fd7 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -13,7 +13,7 @@
   echo "  -p, --pep8               Just run pep8"
   echo "  -c, --coverage           Generate coverage report"
   echo "  -h, --help               Print this usage message"
-  echo "  -d, --debug              Debug this script -- set -o xtrace"
+  echo "  -d, --debug              Run tests with testtools instead of testr. This allows you to use PDB"
   echo "  -- [TESTROPTIONS]        After the first '--' you can pass arbitrary arguments to testr "
 }
 
@@ -25,6 +25,7 @@
 always_venv=0
 never_venv=0
 no_site_packages=0
+debug=0
 force=0
 coverage=0
 wrapper=""
@@ -48,7 +49,7 @@
     -n|--no-site-packages) no_site_packages=1;;
     -f|--force) force=1;;
     -u|--update) update=1;;
-    -d|--debug) set -o xtrace;;
+    -d|--debug) debug=1;;
     -p|--pep8) let just_pep8=1;;
     -c|--coverage) coverage=1;;
     -t|--serial) serial=1;;
@@ -75,6 +76,14 @@
   testr_init
   ${wrapper} find . -type f -name "*.pyc" -delete
   export OS_TEST_PATH=./tempest/tests
+  if [ $debug -eq 1 ]; then
+      if [ "$testrargs" = "" ]; then
+          testrargs="discover ./tempest/tests"
+      fi
+      ${wrapper} python -m testtools.run $testrargs
+      return $?
+  fi
+
   if [ $serial -eq 1 ]; then
       ${wrapper} testr run --subunit $testrargs | ${wrapper} subunit-2to1 | ${wrapper} tools/colorizer.py
   else