diff --git a/s3tests_boto3/functional/test_s3.py b/s3tests_boto3/functional/test_s3.py
index 1a085bd..b8a6142 100644
--- a/s3tests_boto3/functional/test_s3.py
+++ b/s3tests_boto3/functional/test_s3.py
@@ -13560,3 +13560,56 @@ def test_multipart_checksum_3parts():
     assert 'ChecksumSHA256' not in response
     response = client.head_object(Bucket=bucket, Key=key, ChecksumMode='ENABLED')
     assert composite_sha256sum == response['ChecksumSHA256']
+
+def test_post_object_upload_checksum():
+    megabytes = 1024 * 1024
+    min_size = 0
+    max_size = 5 * megabytes
+    test_payload_size = 2 * megabytes
+
+    bucket_name = get_new_bucket()
+    client = get_client()
+
+    url = _get_post_url(bucket_name)
+    utc = pytz.utc
+    expires = datetime.datetime.now(utc) + datetime.timedelta(seconds=+6000)
+
+    policy_document = {"expiration": expires.strftime("%Y-%m-%dT%H:%M:%SZ"),\
+    "conditions": [\
+    {"bucket": bucket_name},\
+    ["starts-with", "$key", "foo_cksum_test"],\
+    {"acl": "private"},\
+    ["starts-with", "$Content-Type", "text/plain"],\
+    ["content-length-range", min_size, max_size],\
+    ]\
+    }
+
+    test_payload = b'x' * test_payload_size
+
+    json_policy_document = json.JSONEncoder().encode(policy_document)
+    bytes_json_policy_document = bytes(json_policy_document, 'utf-8')
+    policy = base64.b64encode(bytes_json_policy_document)
+    aws_secret_access_key = get_main_aws_secret_key()
+    aws_access_key_id = get_main_aws_access_key()
+
+    signature = base64.b64encode(hmac.new(bytes(aws_secret_access_key, 'utf-8'), policy, hashlib.sha1).digest())
+
+    # good checksum payload (checked via upload from awscli)
+    payload = OrderedDict([ ("key" , "foo_cksum_test.txt"),("AWSAccessKeyId" , aws_access_key_id),\
+    ("acl" , "private"),("signature" , signature),("policy" , policy),\
+    ("Content-Type" , "text/plain"),\
+    ('x-amz-checksum-sha256', 'aTL9MeXa9HObn6eP93eygxsJlcwdCwCTysgGAZAgE7w='),\
+    ('file', (test_payload)),])
+
+    r = requests.post(url, files=payload, verify=get_config_ssl_verify())
+    assert r.status_code == 204
+
+    # bad checksum payload
+    payload = OrderedDict([ ("key" , "foo_cksum_test.txt"),("AWSAccessKeyId" , aws_access_key_id),\
+    ("acl" , "private"),("signature" , signature),("policy" , policy),\
+    ("Content-Type" , "text/plain"),\
+    ('x-amz-checksum-sha256', 'sailorjerry'),\
+    ('file', (test_payload)),])
+
+    r = requests.post(url, files=payload, verify=get_config_ssl_verify())
+    assert r.status_code == 400