diff -u -r email.orig/header.py email/header.py
--- email.orig/header.py	2010-09-28 09:13:07.000000000 +0900
+++ email/header.py	2010-09-28 10:36:05.000000000 +0900
@@ -32,15 +32,17 @@
 
 # Match encoded-word strings in the form =?charset?q?Hello_World?=
 ecre = re.compile(r'''
+  (?:[ \t]|^)           # whitespace or the start of the string
   =\?                   # literal =?
   (?P<charset>[^?]*?)   # non-greedy up to the next ? is the charset
   \?                    # literal ?
   (?P<encoding>[qb])    # either a "q" or a "b", case insensitive
   \?                    # literal ?
-  (?P<encoded>.*?)      # non-greedy up to the next ?= is the encoded string
+  (?P<encoded>[^? \t]*?) # literal ? and SPACE are excluded from encoded-text
+                        # non-greedy up to the next ?= is the encoded string
   \?=                   # literal ?=
   (?=[ \t]|$)           # whitespace or the end of the string
-  ''', re.VERBOSE | re.IGNORECASE | re.MULTILINE)
+  ''', re.VERBOSE | re.IGNORECASE)
 
 # Field name regexp, including trailing colon, but not separating whitespace,
 # according to RFC 2822.  Character range is from tilde to exclamation mark.
diff -u -r email.orig/test/test_email.py email/test/test_email.py
--- email.orig/test/test_email.py	2010-09-28 09:13:07.000000000 +0900
+++ email/test/test_email.py	2010-09-28 09:09:24.000000000 +0900
@@ -1556,6 +1556,20 @@
         dh = decode_header(s)
         self.assertEqual(dh, [(s, None)])
 
+    def test_rfc2047_without_whitespace2(self):
+        s = """[Apache-Users 7784] ServerAlias =?ISO-2022-JP?B?GyRAGyRCJEsbKEI=?=:(
+ =?ISO-2022-JP?B?GyRCJTMlbSVzGyhC?=)=?ISO-2022-JP?B?GyRCJHI7SBsoQg==?=
+ =?ISO-2022-JP?B?GyRAGyRCTVEkOSRrJEg1c0YwJCwkKiQrJDckJBsoQg==?="""
+        dh = decode_header(s)
+        self.assertEqual(dh, [('[Apache-Users 7784] ServerAlias =?ISO-2022-JP?B?GyRAGyRCJEsbKEI=?=:(', None),
+        (' =?ISO-2022-JP?B?GyRCJTMlbSVzGyhC?=)=?ISO-2022-JP?B?GyRCJHI7SBsoQg==?=', None), 
+        ('\x1b$@\x1b$BMQ$9$k$H5sF0$,$*$+$7$$\x1b(B', 'iso-2022-jp')])
+
+    def test_rfc2047_without_whitespace3(self):
+        s = 'Python=?ISO-2022-JP?B?GyRCJWEhPCVqJXMlMCVqJTklSBsoQg==?= Japan'
+        dh = decode_header(s)
+        self.assertEqual(dh, [('Python=?ISO-2022-JP?B?GyRCJWEhPCVqJXMlMCVqJTklSBsoQg==?= Japan', None)])
+
     def test_rfc2047_with_whitespace(self):
         s = 'Sm =?ISO-8859-1?B?9g==?= rg =?ISO-8859-1?B?5Q==?= sbord'
         dh = decode_header(s)