diff --git a/blacken_docs.py b/blacken_docs.py
index 86ffc8c..8992117 100644
--- a/blacken_docs.py
+++ b/blacken_docs.py
@@ -128,6 +128,8 @@ def _rst_match(match: Match[str]) -> str:
         return f'{match["before"]}{code.rstrip()}{trailing_ws}'
 
     def _rst_literal_blocks_match(match: Match[str]) -> str:
+        if not match['code'].strip():
+            return match[0]
         min_indent = min(INDENT_RE.findall(match['code']))
         trailing_ws_match = TRAILING_NL_RE.search(match['code'])
         assert trailing_ws_match
diff --git a/tests/blacken_docs_test.py b/tests/blacken_docs_test.py
index c17f3ae..5c9114d 100644
--- a/tests/blacken_docs_test.py
+++ b/tests/blacken_docs_test.py
@@ -234,6 +234,23 @@ def test_format_src_rst_literal_blocks_nested():
     assert errors == []
 
 
+def test_format_src_rst_literal_blocks_empty():
+    before = dedent(
+        '''
+        Example::
+
+        .. warning::
+
+            There was no example.
+        ''',
+    )
+    after, errors = blacken_docs.format_str(
+        before, BLACK_MODE, rst_literal_blocks=True,
+    )
+    assert after == before
+    assert errors == []
+
+
 def test_format_src_rst_sphinx_doctest():
     before = (
         '.. testsetup:: group1\n'