diff --git a/.ci/mitogen_py24_install.py b/.ci/mitogen_py24_install.py
new file mode 100755
index 00000000..97370806
--- /dev/null
+++ b/.ci/mitogen_py24_install.py
@@ -0,0 +1,14 @@
+#!/usr/bin/env python
+
+import ci_lib
+
+batches = [
+    [
+        'docker pull %s' % (ci_lib.image_for_distro(ci_lib.DISTRO),),
+    ],
+    [
+        'sudo tar -C / -jxvf tests/data/ubuntu-python-2.4.6.tar.bz2',
+    ]
+]
+
+ci_lib.run_batches(batches)
diff --git a/.ci/mitogen_py24_tests.py b/.ci/mitogen_py24_tests.py
new file mode 100755
index 00000000..228e79bd
--- /dev/null
+++ b/.ci/mitogen_py24_tests.py
@@ -0,0 +1,17 @@
+#!/usr/bin/env python
+# Mitogen tests for Python 2.4.
+
+import os
+
+import ci_lib
+
+os.environ.update({
+    'NOCOVERAGE': '1',
+    'UNIT2': '/usr/local/python2.4.6/bin/unit2',
+
+    'MITOGEN_TEST_DISTRO': ci_lib.DISTRO,
+    'MITOGEN_LOG_LEVEL': 'debug',
+    'SKIP_ANSIBLE': '1',
+})
+
+ci_lib.run('./run_tests -v')
diff --git a/run_tests b/run_tests
index 8de99ace..9ffeab17 100755
--- a/run_tests
+++ b/run_tests
@@ -8,16 +8,25 @@ echo
 set -o errexit
 set -o pipefail
 
-UNIT2="$(which unit2)"
+if [ ! "$UNIT2" ]; then
+    UNIT2="$(which unit2)"
+fi
 
-coverage erase
+[ "$NOCOVERAGE" ] || coverage erase
 
 # First run overwites coverage output.
 [ "$SKIP_MITOGEN" ] || {
-    coverage run "${UNIT2}" discover \
-                            --start-directory "tests" \
-                            --pattern '*_test.py' \
-                            "$@"
+    if [ ! "$NOCOVERAGE" ]; then
+        coverage run "${UNIT2}" discover \
+            --start-directory "tests" \
+            --pattern '*_test.py' \
+            "$@"
+    else
+        "${UNIT2}" discover \
+            --start-directory "tests" \
+            --pattern '*_test.py' \
+            "$@"
+    fi
 }
 
 # Second run appends. This is since 'discover' treats subdirs as packages and
@@ -27,11 +36,18 @@ coverage erase
 # mess of Git history.
 [ "$SKIP_ANSIBLE" ] || {
     export PYTHONPATH=`pwd`/tests:$PYTHONPATH
-    coverage run -a "${UNIT2}" discover \
-                            --start-directory "tests/ansible" \
-                            --pattern '*_test.py' \
-                            "$@"
+    if [ ! "$NOCOVERAGE" ]; then
+        coverage run -a "${UNIT2}" discover \
+            --start-directory "tests/ansible" \
+            --pattern '*_test.py' \
+            "$@"
+    else
+        coverage run -a "${UNIT2}" discover \
+            --start-directory "tests/ansible" \
+            --pattern '*_test.py' \
+            "$@"
+    fi
 }
 
-coverage html
-echo coverage report is at "file://$(pwd)/htmlcov/index.html"
+[ "$NOCOVERAGE" ] || coverage html
+[ "$NOCOVERAGE" ] || echo coverage report is at "file://$(pwd)/htmlcov/index.html"