diff -ur a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
--- a/Lib/test/test_bytes.py	2016-12-09 19:05:07.000000000 -0500
+++ b/Lib/test/test_bytes.py	2016-12-09 19:05:51.000000000 -0500
@@ -293,6 +293,7 @@
         b = bytearray([0x1a, 0x2b, 0x30])
         self.assertEqual(self.type2test.fromhex('1a2B30'), b)
         self.assertEqual(self.type2test.fromhex('  1A 2B  30   '), b)
+        self.assertEqual(self.type2test.fromhex(' 1A\n2B\t30\v'), b)
         self.assertEqual(self.type2test.fromhex('0000'), b'\0\0')
         self.assertRaises(TypeError, self.type2test.fromhex, b'1B')
         self.assertRaises(ValueError, self.type2test.fromhex, 'a')
diff -ur a/Objects/bytesobject.c b/Objects/bytesobject.c
--- a/Objects/bytesobject.c	2016-12-09 19:01:49.000000000 -0500
+++ b/Objects/bytesobject.c	2016-12-09 19:02:39.000000000 -0500
@@ -2379,10 +2379,10 @@
     end = str + hexlen;
     while (str < end) {
         /* skip over spaces in the input */
-        if (*str == ' ') {
+        if (Py_ISSPACE(*str)) {
             do {
                 str++;
-            } while (*str == ' ');
+            } while (Py_ISSPACE(*str));
             if (str >= end)
                 break;
         }