diff --git a/Lib/test/test_urllib.py b/Lib/test/test_urllib.py
index 58ca2a5..d8afce2 100644
--- a/Lib/test/test_urllib.py
+++ b/Lib/test/test_urllib.py
@@ -1407,8 +1407,12 @@ class RequestTests(unittest.TestCase):
         Request = urllib.request.Request
         request = Request("http://www.python.org")
         self.assertEqual(request.get_method(), 'GET')
+        request = Request("http://www.python.org", None)
+        self.assertEqual(request.get_method(), 'GET')
         request = Request("http://www.python.org", {})
         self.assertEqual(request.get_method(), 'POST')
+        request = Request("http://www.python.org", b'')
+        self.assertEqual(request.get_method(), 'POST')
 
     def test_with_method_arg(self):
         Request = urllib.request.Request
@@ -1424,6 +1428,15 @@ class RequestTests(unittest.TestCase):
         self.assertEqual(request.get_method(), 'HEAD')
 
 
+    def test_with_invalid_param_type(self):
+        Request = urllib.request.Request
+        with self.assertRaisesRegex(TypeError, "url should be of type str"):
+            request = Request(b"http://www.python.org")
+        with self.assertRaisesRegex(TypeError, "POST data cannot be of type str"):
+            request = Request("http://www.python.org", urllib.parse.urlencode({}))
+        with self.assertRaisesRegex(TypeError,"Key should be type of bytes in POST data"):
+            request = Request("http://www.python.org", {'abc': 1})
+
 class URL2PathNameTests(unittest.TestCase):
 
     def test_converting_drive_letter(self):
diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
index e6abf34..6b9ca29 100644
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -353,6 +353,8 @@ class Request:
 
     @full_url.setter
     def full_url(self, url):
+        if not isinstance(url, str):
+            raise TypeError("url should be of type str")
         # unwrap('<URL:type://host/path>') --> 'type://host/path'
         self._full_url = unwrap(url)
         self._full_url, self.fragment = splittag(self._full_url)
@@ -370,6 +372,14 @@ class Request:
 
     @data.setter
     def data(self, data):
+        if isinstance(data, str):
+            raise TypeError("POST data cannot be of type str")
+
+        if isinstance(data, dict):
+            for k in data.keys():
+                if not isinstance(k, bytes):
+                    raise TypeError("Key should be type of bytes in POST data")
+
         if data != self._data:
             self._data = data
             # issue 16464