diff --git a/mangum/handlers/aws_alb.py b/mangum/handlers/aws_alb.py
index b2c64709..33e0968f 100644
--- a/mangum/handlers/aws_alb.py
+++ b/mangum/handlers/aws_alb.py
@@ -57,9 +57,13 @@ def request(self) -> Request:
 
     @property
     def body(self) -> bytes:
-        body = self.trigger_event.get("body", b"")
+        body = self.trigger_event.get("body", b"") or b""
+
         if self.trigger_event.get("isBase64Encoded", False):
-            body = base64.b64decode(body)
+            return base64.b64decode(body)
+        if not isinstance(body, bytes):
+            body = body.encode()
+
         return body
 
     def transform_response(self, response: Response) -> Dict[str, Any]:
diff --git a/mangum/handlers/aws_api_gateway.py b/mangum/handlers/aws_api_gateway.py
index 6267ffa3..2e239d44 100644
--- a/mangum/handlers/aws_api_gateway.py
+++ b/mangum/handlers/aws_api_gateway.py
@@ -95,9 +95,13 @@ def request(self) -> Request:
 
     @property
     def body(self) -> bytes:
-        body = self.trigger_event.get("body", b"")
+        body = self.trigger_event.get("body", b"") or b""
+
         if self.trigger_event.get("isBase64Encoded", False):
-            body = base64.b64decode(body)
+            return base64.b64decode(body)
+        if not isinstance(body, bytes):
+            body = body.encode()
+
         return body
 
     def transform_response(self, response: Response) -> Dict[str, Any]:
diff --git a/mangum/handlers/aws_cf_lambda_at_edge.py b/mangum/handlers/aws_cf_lambda_at_edge.py
index 85013bd3..b43132c3 100644
--- a/mangum/handlers/aws_cf_lambda_at_edge.py
+++ b/mangum/handlers/aws_cf_lambda_at_edge.py
@@ -55,9 +55,13 @@ def request(self) -> Request:
     @property
     def body(self) -> bytes:
         request = self.trigger_event["Records"][0]["cf"]["request"]
-        body = request.get("body", {}).get("data", None)
+        body = request.get("body", {}).get("data", None) or b""
+
         if request.get("body", {}).get("encoding", "") == "base64":
-            body = base64.b64decode(body)
+            return base64.b64decode(body)
+        if not isinstance(body, bytes):
+            body = body.encode()
+
         return body
 
     def transform_response(self, response: Response) -> Dict[str, Any]:
diff --git a/mangum/handlers/aws_http_gateway.py b/mangum/handlers/aws_http_gateway.py
index 6ff783cd..513c4942 100644
--- a/mangum/handlers/aws_http_gateway.py
+++ b/mangum/handlers/aws_http_gateway.py
@@ -102,9 +102,13 @@ def request(self) -> Request:
 
     @property
     def body(self) -> bytes:
-        body = self.trigger_event.get("body", b"")
+        body = self.trigger_event.get("body", b"") or b""
+
         if self.trigger_event.get("isBase64Encoded", False):
-            body = base64.b64decode(body)
+            return base64.b64decode(body)
+        if not isinstance(body, bytes):
+            body = body.encode()
+
         return body
 
     def transform_response(self, response: Response) -> Dict[str, Any]:
diff --git a/tests/handlers/test_aws_alb.py b/tests/handlers/test_aws_alb.py
index 216d8a8d..d922c37d 100644
--- a/tests/handlers/test_aws_alb.py
+++ b/tests/handlers/test_aws_alb.py
@@ -74,6 +74,8 @@ def test_aws_alb_basic():
 
     example_context = {}
     handler = AwsAlb(example_event, example_context)
+
+    assert type(handler.body) == bytes
     assert handler.request.scope == {
         "asgi": {"version": "3.0"},
         "aws.context": {},
@@ -119,7 +121,15 @@ def test_aws_alb_basic():
     "query_string,scope_body",
     [
         ("GET", "/hello/world", None, None, False, b"", None),
-        ("POST", "/", {"name": ["me"]}, None, False, b"name=me", None),
+        (
+            "POST",
+            "/",
+            {"name": ["me"]},
+            "field1=value1&field2=value2",
+            False,
+            b"name=me",
+            b"field1=value1&field2=value2",
+        ),
         (
             "GET",
             "/my/resource",
@@ -210,7 +220,10 @@ def test_aws_alb_scope_real(
         "type": "http",
     }
 
-    assert handler.body == scope_body
+    if handler.body:
+        assert handler.body == scope_body
+    else:
+        assert handler.body == b""
 
 
 def test_aws_alb_set_cookies() -> None:
diff --git a/tests/handlers/test_aws_api_gateway.py b/tests/handlers/test_aws_api_gateway.py
index bc07d080..e35bf4e8 100644
--- a/tests/handlers/test_aws_api_gateway.py
+++ b/tests/handlers/test_aws_api_gateway.py
@@ -96,6 +96,8 @@ def test_aws_api_gateway_scope_basic():
     }
     example_context = {}
     handler = AwsApiGateway(example_event, example_context)
+
+    assert type(handler.body) == bytes
     assert handler.request.scope == {
         "asgi": {"version": "3.0"},
         "aws.context": {},
@@ -128,7 +130,15 @@ def test_aws_api_gateway_scope_basic():
     "query_string,scope_body",
     [
         ("GET", "/hello/world", None, None, False, b"", None),
-        ("POST", "/", {"name": ["me"]}, None, False, b"name=me", None),
+        (
+            "POST",
+            "/",
+            {"name": ["me"]},
+            "field1=value1&field2=value2",
+            False,
+            b"name=me",
+            b"field1=value1&field2=value2",
+        ),
         (
             "GET",
             "/my/resource",
@@ -218,7 +228,10 @@ def test_aws_api_gateway_scope_real(
         "type": "http",
     }
 
-    assert handler.body == scope_body
+    if handler.body:
+        assert handler.body == scope_body
+    else:
+        assert handler.body == b""
 
 
 @pytest.mark.parametrize(
diff --git a/tests/handlers/test_aws_cf_lambda_at_edge.py b/tests/handlers/test_aws_cf_lambda_at_edge.py
index 650e4e2d..4692e791 100644
--- a/tests/handlers/test_aws_cf_lambda_at_edge.py
+++ b/tests/handlers/test_aws_cf_lambda_at_edge.py
@@ -136,6 +136,7 @@ def test_aws_cf_lambda_at_edge_scope_basic():
     example_context = {}
     handler = AwsCfLambdaAtEdge(example_event, example_context)
 
+    assert type(handler.body) == bytes
     assert handler.request.scope == {
         "asgi": {"version": "3.0"},
         "aws.context": {},
@@ -169,7 +170,15 @@ def test_aws_cf_lambda_at_edge_scope_basic():
     "body_base64_encoded,query_string,scope_body",
     [
         ("GET", "/hello/world", None, None, False, b"", None),
-        ("POST", "/", {"name": ["me"]}, None, False, b"name=me", None),
+        (
+            "POST",
+            "/",
+            {"name": ["me"]},
+            "field1=value1&field2=value2",
+            False,
+            b"name=me",
+            b"field1=value1&field2=value2",
+        ),
         (
             "GET",
             "/my/resource",
@@ -241,7 +250,10 @@ def test_aws_api_gateway_scope_real(
         "type": "http",
     }
 
-    assert handler.body == scope_body
+    if handler.body:
+        assert handler.body == scope_body
+    else:
+        assert handler.body == b""
 
 
 @pytest.mark.parametrize(
diff --git a/tests/handlers/test_aws_http_gateway.py b/tests/handlers/test_aws_http_gateway.py
index 56b9115e..4e87f9df 100644
--- a/tests/handlers/test_aws_http_gateway.py
+++ b/tests/handlers/test_aws_http_gateway.py
@@ -195,6 +195,8 @@ def test_aws_http_gateway_scope_basic_v1():
     }
     example_context = {}
     handler = AwsHttpGateway(example_event, example_context)
+
+    assert type(handler.body) == bytes
     assert handler.request.scope == {
         "asgi": {"version": "3.0"},
         "aws.context": {},
@@ -297,6 +299,8 @@ def test_aws_http_gateway_scope_basic_v2():
     }
     example_context = {}
     handler = AwsHttpGateway(example_event, example_context)
+
+    assert type(handler.body) == bytes
     assert handler.request.scope == {
         "asgi": {"version": "3.0"},
         "aws.context": {},
@@ -396,7 +400,10 @@ def test_aws_http_gateway_scope_real_v1(
         "type": "http",
     }
 
-    assert handler.body == scope_body
+    if handler.body:
+        assert handler.body == scope_body
+    else:
+        assert handler.body == b""
 
 
 @pytest.mark.parametrize(
@@ -461,7 +468,10 @@ def test_aws_http_gateway_scope_real_v2(
         "type": "http",
     }
 
-    assert handler.body == scope_body
+    if handler.body:
+        assert handler.body == scope_body
+    else:
+        assert handler.body == b""
 
 
 @pytest.mark.parametrize(