diff --git a/layer/nrlf/core/decorators.py b/layer/nrlf/core/decorators.py
index 683ca3e00..f2dc724db 100644
--- a/layer/nrlf/core/decorators.py
+++ b/layer/nrlf/core/decorators.py
@@ -236,15 +236,23 @@ def request_handler(
     """
 
     def wrapped_func(func: RequestHandler):
-        def wrapper(*args, **kwargs):
-            event: APIGatewayProxyEvent = args[0]
-            context: LambdaContext = args[1]
+        def wrapper(event: APIGatewayProxyEvent, context: LambdaContext, **kwargs):
+            client_cert = event.request_context.identity.client_cert
+            if client_cert:
+                client_cert_info = {
+                    "subject_dn": client_cert.subject_dn,
+                    "issuer_dn": client_cert.issuer_dn,
+                    "serial_number": client_cert.serial_number,
+                }
+            else:
+                client_cert_info = "No client certificate provided"
 
             logger.log(
                 code=LogReference.HANDLER000,
                 method=event.http_method,
                 path=event.path,
                 headers=event.headers,
+                client_cert_info=client_cert_info,
             )
 
             if skip_request_verification:
diff --git a/layer/nrlf/core/tests/test_decorators.py b/layer/nrlf/core/tests/test_decorators.py
index ea9d65717..9188a0e47 100644
--- a/layer/nrlf/core/tests/test_decorators.py
+++ b/layer/nrlf/core/tests/test_decorators.py
@@ -1,5 +1,6 @@
 import json
 import warnings
+from typing import Any
 
 import pytest
 from aws_lambda_powertools.utilities.data_classes import APIGatewayProxyEvent
@@ -288,6 +289,74 @@ def decorated_function(event):
     )
 
 
+def test_log_includes_client_cert_details(mocker: MockerFixture):
+    @request_handler()
+    def decorated_function() -> Response:
+        return Response(
+            statusCode="200",
+            body=json.dumps({"message": "Hello, World!"}),
+            headers={"Content-Type": "application/json"},
+        )
+
+    test_event = create_test_api_gateway_event()
+    event = APIGatewayProxyEvent(test_event)
+
+    mock_logger = mocker.patch("nrlf.core.decorators.logger")
+
+    decorated_function(event, create_mock_context())
+
+    assert any(
+        call[1]["code"].name == "HANDLER000"
+        for call in mock_logger.log.call_args_list
+        if call[1]
+    )
+
+    logged_cert_info: dict[str, Any] = [
+        call[1:][0]
+        for call in mock_logger.log.call_args_list
+        if call[1] and "code" in call[1] and call[1]["code"].name == "HANDLER000"
+    ][0]["client_cert_info"]
+
+    client_cert = event.request_context.identity.client_cert
+    assert logged_cert_info == {
+        "subject_dn": client_cert.subject_dn,
+        "issuer_dn": client_cert.issuer_dn,
+        "serial_number": client_cert.serial_number,
+    }
+
+
+def test_log_includes_client_cert_details_when_no_cert(mocker: MockerFixture):
+    @request_handler()
+    def decorated_function() -> Response:
+        return Response(
+            statusCode="200",
+            body=json.dumps({"message": "Hello, World!"}),
+            headers={"Content-Type": "application/json"},
+        )
+
+    test_event = create_test_api_gateway_event()
+    test_event["requestContext"]["identity"]["clientCert"] = None
+    event = APIGatewayProxyEvent(test_event)
+
+    mock_logger = mocker.patch("nrlf.core.decorators.logger")
+
+    decorated_function(event, create_mock_context())
+
+    assert any(
+        call[1]["code"].name == "HANDLER000"
+        for call in mock_logger.log.call_args_list
+        if call[1]
+    )
+
+    logged_cert_info: dict[str, Any] = [
+        call[1:][0]
+        for call in mock_logger.log.call_args_list
+        if call[1] and "code" in call[1] and call[1]["code"].name == "HANDLER000"
+    ][0]["client_cert_info"]
+
+    assert logged_cert_info == "No client certificate provided"
+
+
 def test_verify_request_id_happy_path():
     test_event = create_test_api_gateway_event()
 
diff --git a/layer/nrlf/tests/events.py b/layer/nrlf/tests/events.py
index c32d7cd31..003fa87c5 100644
--- a/layer/nrlf/tests/events.py
+++ b/layer/nrlf/tests/events.py
@@ -55,6 +55,13 @@ def create_test_api_gateway_event(
             "resourcePath": "/",
             "httpMethod": "GET",
             "path": "/Prod/",
+            "identity": {
+                "clientCert": {
+                    "subjectDN": "CN=TEST SUBJECT",
+                    "issuerDN": "CN=TEST ISSUER",
+                    "serialNumber": "0000001",
+                }
+            },
         },
         "headers": headers or create_headers(),
         "multiValueHeaders": {},