diff --git a/Library/Homebrew/test/test_versions.rb b/Library/Homebrew/test/test_versions.rb
index 52352ce8d0..e520ad55ef 100644
--- a/Library/Homebrew/test/test_versions.rb
+++ b/Library/Homebrew/test/test_versions.rb
@@ -353,7 +353,13 @@ class VersionParsingTests < Homebrew::TestCase
   def test_with_arch
     assert_version_detected '4.0.18-1',
       'http://ftpmirror.gnu.org/mtools/mtools-4.0.18-1.i686.rpm'
+    assert_version_detected '5.5.7-5',
+      'http://ftpmirror.gnu.org/autogen/autogen-5.5.7-5.i386.rpm'
     assert_version_detected '2.8',
       'http://ftpmirror.gnu.org/libtasn1/libtasn1-2.8-x86.zip'
+    assert_version_detected '2.8',
+      'http://ftpmirror.gnu.org/libtasn1/libtasn1-2.8-x64.zip'
+    assert_version_detected '4.0.18',
+      'http://ftpmirror.gnu.org/mtools/mtools_4.0.18_i386.deb'
   end
 end
diff --git a/Library/Homebrew/version.rb b/Library/Homebrew/version.rb
index f946452085..63bccdba48 100644
--- a/Library/Homebrew/version.rb
+++ b/Library/Homebrew/version.rb
@@ -273,8 +273,9 @@ class Version
     return m.captures.first.gsub('_', '.') unless m.nil?
 
     # e.g. foobar-4.5.1-1
+    # e.g. unrtf_0.20.4-1
     # e.g. ruby-1.9.1-p243
-    m = /-((?:\d+\.)*\d\.\d+-(?:p|rc|RC)?\d+)(?:[-._](?:bin|dist|stable|src|sources))?$/.match(stem)
+    m = /[-_]((?:\d+\.)*\d\.\d+-(?:p|rc|RC)?\d+)(?:[-._](?:bin|dist|stable|src|sources))?$/.match(stem)
     return m.captures.first unless m.nil?
 
     # e.g. lame-398-1
@@ -299,8 +300,11 @@ class Version
     return m.captures.first unless m.nil?
 
     # e.g. http://ftpmirror.gnu.org/mtools/mtools-4.0.18-1.i686.rpm
+    # e.g. http://ftpmirror.gnu.org/autogen/autogen-5.5.7-5.i386.rpm
     # e.g. http://ftpmirror.gnu.org/libtasn1/libtasn1-2.8-x86.zip
-    m = /-(\d+\.\d+(?:\.\d+)?(?:-\d+)?)[-_.](?:i686|x86(?:[-_](?:32|64))?)$/.match(stem)
+    # e.g. http://ftpmirror.gnu.org/libtasn1/libtasn1-2.8-x64.zip
+    # e.g. http://ftpmirror.gnu.org/mtools/mtools_4.0.18_i386.deb
+    m = /[-_](\d+\.\d+(?:\.\d+)?(?:-\d+)?)[-_.](?:i[36]86|x86|x64(?:[-_](?:32|64))?)$/.match(stem)
     return m.captures.first unless m.nil?
 
     # e.g. foobar4.5.1