diff --git a/lib/compass/sass_extensions/functions/font_files.rb b/lib/compass/sass_extensions/functions/font_files.rb
index c18ce05a..f7f72d27 100644
--- a/lib/compass/sass_extensions/functions/font_files.rb
+++ b/lib/compass/sass_extensions/functions/font_files.rb
@@ -1,10 +1,39 @@
 module Compass::SassExtensions::Functions::FontFiles
+  FONT_TYPES = {
+    :woff => 'woff',
+    :otf => 'opentype',
+    :opentype => 'opentype',
+    :ttf => 'truetype',
+    :truetype => 'truetype',
+    :svg => 'svg'
+  }
+
   def font_files(*args)
-    raise Sass::SyntaxError, "An even number of arguments must be passed to font_files()" unless args.size % 2 == 0
     files = []
-    while args.size > 0
-      files << "#{font_url(args.shift)} format('#{args.shift}')"
+    args_length = args.length
+    skip_next = false
+
+    args.each_with_index do |arg, index|
+      if skip_next
+        skip_next = false
+        next
+      end
+
+      type = (args_length > (index + 1)) ? args[index + 1].value.to_sym : :wrong
+
+      if FONT_TYPES.key? type
+        skip_next = true
+      else
+        type = arg.to_s.split('.').last.gsub('"', '').to_sym
+      end
+
+      if FONT_TYPES.key? type
+        files << "#{font_url(arg)} format('#{FONT_TYPES[type]}')"
+      else
+        raise Sass::SyntaxError, "Could not determine font type for #{arg}"
+      end
     end
+
     Sass::Script::String.new(files.join(", "))
   end
 end
diff --git a/test/units/sass_extensions_test.rb b/test/units/sass_extensions_test.rb
index 5ee96b7d..d965dcc9 100644
--- a/test/units/sass_extensions_test.rb
+++ b/test/units/sass_extensions_test.rb
@@ -101,9 +101,26 @@ class SassExtensionsTest < Test::Unit::TestCase
   def test_font_files
     assert_equal '', evaluate('font_files()')
     assert_equal "url(/font/name.woff) format('woff'), url(/fonts/name.ttf) format('truetype'), url(/fonts/name.svg#fontpath) format('svg')", evaluate("font-files('/font/name.woff', woff, '/fonts/name.ttf', truetype, '/fonts/name.svg#fontpath', svg)")
-    assert_raises Sass::SyntaxError do
+
+    assert_equal "url(/font/with/right_ext.woff) format('woff')", evaluate("font_files('/font/with/right_ext.woff')")
+    assert_equal "url(/font/with/wrong_ext.woff) format('svg')", evaluate("font_files('/font/with/wrong_ext.woff', 'svg')")
+    assert_equal "url(/font/with/no_ext) format('opentype')", evaluate("font_files('/font/with/no_ext', 'otf')")
+    assert_equal "url(/font/with/weird.ext) format('truetype')", evaluate("font_files('/font/with/weird.ext', 'ttf')")
+
+    assert_equal "url(/font/with/right_ext.woff) format('woff'), url(/font/with/right_ext_also.otf) format('opentype')", evaluate("font_files('/font/with/right_ext.woff', '/font/with/right_ext_also.otf')")
+    assert_equal "url(/font/with/wrong_ext.woff) format('truetype'), url(/font/with/right_ext.otf) format('opentype')", evaluate("font_files('/font/with/wrong_ext.woff', 'ttf', '/font/with/right_ext.otf')")
+
+    assert_nothing_raised Sass::SyntaxError do
       evaluate("font-files('/font/name.woff')")
     end
+
+    assert_raises Sass::SyntaxError do
+      evaluate("font-files('/font/name.ext')")
+    end
+
+    assert_raises Sass::SyntaxError do
+      evaluate("font-files('/font/name.ext', 'nonsense')")
+    end
   end
 
   %w(stylesheet_url font_url image_url generated_image_url).each do |helper|