diff --git a/scipy/conftest.py b/scipy/conftest.py
index e5fac23..1a971e8 100644
--- a/scipy/conftest.py
+++ b/scipy/conftest.py
@@ -37,3 +38,15 @@ def check_fpu_mode(request):
         warnings.warn("FPU mode changed from {0:#x} to {1:#x} during "
                       "the test".format(old_mode, new_mode),
                       category=FPUModeChangeWarning, stacklevel=0)
+
+
+ACCEPTABLE_FAILURE_RATE = int(os.environ.get('ACCEPTABLE_FAILURE_RATE', 0))
+
+
+@pytest.hookimpl()
+def pytest_sessionfinish(session, exitstatus):
+    if exitstatus != 1:
+        return
+    failure_rate = (100.0 * session.testsfailed) / session.testscollected
+    if failure_rate <= ACCEPTABLE_FAILURE_RATE:
+        session.exitstatus = 0