diff --git a/lib/linguist/blob.rb b/lib/linguist/blob.rb
index 95e30b83..755c1352 100644
--- a/lib/linguist/blob.rb
+++ b/lib/linguist/blob.rb
@@ -26,8 +26,12 @@ module Linguist
       defined?(Grit::Submodule) && @blob.kind_of?(Grit::Submodule)
     end
 
+    def binary?
+      mime_type == 'octet-stream' || !(text? || image?)
+    end
+
     def file?
-      image? || !text? || mime_type == 'octet-stream'
+      image? || binary?
     end
 
     def text?
diff --git a/test/test_blob.rb b/test/test_blob.rb
index 24ccfb2c..09b19888 100644
--- a/test/test_blob.rb
+++ b/test/test_blob.rb
@@ -50,6 +50,14 @@ class TestBlob < Test::Unit::TestCase
     assert_equal 15, blob("foo.rb").size
   end
 
+  def test_binary
+    assert blob("linguist.gem").binary?
+    assert blob("git.deb").binary?
+    assert blob("git.exe").binary?
+    assert !blob("file.txt").binary?
+    assert !blob("octocat.png").binary?
+  end
+
   def test_file
     assert blob("octocat.png").file?
     assert blob("linguist.gem").file?