diff --git django/utils/html.py django/utils/html.py
index 78359f9..6760f7a 100644
--- django/utils/html.py
+++ django/utils/html.py
@@ -20,8 +20,8 @@ DOTS = [u'·', u'*', u'\u2022', u'•', u'•', u'•']
 unencoded_ampersands_re = re.compile(r'&(?!(\w+|#\d+);)')
 unquoted_percents_re = re.compile(r'%(?![0-9A-Fa-f]{2})')
 word_split_re = re.compile(r'(\s+)')
-simple_url_re = re.compile(r'^https?://\w')
-simple_url_2_re = re.compile(r'^www\.|^(?!http)\w[^@]+\.(com|edu|gov|int|mil|net|org)$')
+simple_url_re = re.compile(r'^https?://\w', re.IGNORECASE)
+simple_url_2_re = re.compile(r'^www\.|^(?!http)\w[^@]+\.(com|edu|gov|int|mil|net|org)$', re.IGNORECASE)
 simple_email_re = re.compile(r'^\S+@\S+\.\S+$')
 link_target_attribute_re = re.compile(r'(<a [^>]*?)target=[^\s>]+')
 html_gunk_re = re.compile(r'(?:<br clear="all">|<i><\/i>|<b><\/b>|<em><\/em>|<strong><\/strong>|<\/?smallcaps>|<\/?uppercase>)', re.IGNORECASE)