diff --git a/elasticsearch_serverless/serializer.py b/elasticsearch_serverless/serializer.py
index 758c6b7..64592d2 100644
--- a/elasticsearch_serverless/serializer.py
+++ b/elasticsearch_serverless/serializer.py
@@ -157,7 +157,6 @@ def _attempt_serialize_numpy(data: Any) -> Tuple[bool, Any]:
         elif isinstance(
             data,
             (
-                np.float_,
                 np.float16,
                 np.float32,
                 np.float64,
diff --git a/test_elasticsearch_serverless/test_serializer.py b/test_elasticsearch_serverless/test_serializer.py
index ee63cc4..4674e97 100644
--- a/test_elasticsearch_serverless/test_serializer.py
+++ b/test_elasticsearch_serverless/test_serializer.py
@@ -90,7 +90,6 @@ def test_serializes_numpy_integers():
 def test_serializes_numpy_floats():
     ser = JSONSerializer()
     for np_type in (
-        np.float_,
         np.float32,
         np.float64,
     ):