diff --git a/jsonschema/tests/fuzz_validate.py b/jsonschema/tests/fuzz_validate.py
index a8c62ac9f..c12e88bcf 100644
--- a/jsonschema/tests/fuzz_validate.py
+++ b/jsonschema/tests/fuzz_validate.py
@@ -36,6 +36,7 @@ def test_schemas(obj1, obj2):
 
 
 def main():
+    atheris.instrument_all()
     atheris.Setup(
         sys.argv,
         test_schemas.hypothesis.fuzz_one_input,