diff --git a/pytest_pudb.py b/pytest_pudb.py
index 1f7a592..0a13897 100644
--- a/pytest_pudb.py
+++ b/pytest_pudb.py
@@ -3,6 +3,7 @@
 import pudb
 import sys
 import warnings
+import _pytest.unittest
 
 
 def pytest_addoption(parser):
@@ -13,10 +14,6 @@ def pytest_addoption(parser):
 
 def pytest_configure(config):
     pudb_wrapper = PuDBWrapper(config)
-
-    if config.getvalue("usepudb"):
-        config.pluginmanager.register(pudb_wrapper, 'pudb_wrapper')
-
     pudb_wrapper.mount()
     config._cleanup.append(pudb_wrapper.unmount)
 
@@ -30,16 +27,38 @@ def __init__(self, config):
         self.config = config
         self.pluginmanager = config.pluginmanager
         self._pudb_get_debugger = None
+        self._test_case_function_runtest = None
+
+    @property
+    def with_pudb_option(self):
+        return self.config.getvalue("usepudb")
 
     def mount(self):
         self._pudb_get_debugger = pudb._get_debugger
         pudb._get_debugger = self._get_debugger
 
+        if self.with_pudb_option:
+            self.config.pluginmanager.register(self, 'pudb_wrapper')
+
+            def runtest(self):
+                # disables tearDown and cleanups for post mortem debugging
+                # see: https://github.com/pytest-dev/pytest/pull/1890
+                if self._handle_skip():
+                    return
+                self._testcase.debug()
+
+            self._test_case_function_runtest = _pytest.unittest.TestCaseFunction.runtest
+            _pytest.unittest.TestCaseFunction.runtest = runtest
+
     def unmount(self):
         if self._pudb_get_debugger:
             pudb._get_debugger = self._pudb_get_debugger
             self._pudb_get_debugger = None
 
+        if self._test_case_function_runtest:
+            _pytest.unittest.TestCaseFunction.runtest = self._test_case_function_runtest
+            self._test_case_function_runtest = None
+
     def disable_io_capture(self):
         if self.pluginmanager is not None:
             capman = self.pluginmanager.getplugin("capturemanager")
diff --git a/test_pytest_pudb.py b/test_pytest_pudb.py
index 6f7b77a..b5e1b62 100644
--- a/test_pytest_pudb.py
+++ b/test_pytest_pudb.py
@@ -18,6 +18,28 @@ def test_1():
     child.sendeof()
 
 
+def test_pudb_unittest_teardown_interaction(testdir):
+    p1 = testdir.makepyfile("""
+        import unittest
+        class Blub(unittest.TestCase):
+            def tearDown(self):
+                self.a = False
+            def test_false(self):
+                self.a = True
+                self.fail()
+    """)
+    child = testdir.spawn_pytest("--pudb %s" % p1)
+    child.expect("PuDB")
+    child.expect(HELP_MESSAGE)
+    child.expect("PROCESSING EXCEPTION")
+    child.expect(VARIABLES_TABLE)
+    child.send('V')  # Move to variables
+    child.send('n')  # Add watch expression
+    child.expect('Add Watch Expression')
+    child.sendline('self.a')  # Set self.a
+    child.expect('self.a: \x1b\\[0;30;42mTrue')
+    child.sendeof()
+
 def test_pudb_set_trace_integration(testdir):
     p1 = testdir.makepyfile("""
         def test_1():