diff --git a/lib/zip/file.rb b/lib/zip/file.rb
index 3cc4c35..4a5267d 100644
--- a/lib/zip/file.rb
+++ b/lib/zip/file.rb
@@ -71,11 +71,12 @@ module Zip
       case
       when !buffer && ::File.size?(file_name)
         @create = nil
-        @exist_file_perms = ::File.stat(file_name).mode
+        @file_permissions = ::File.stat(file_name).mode
         ::File.open(name, 'rb') do |f|
           read_from_stream(f)
         end
       when create
+        @file_permissions = create_file_permissions
         @entry_set = EntrySet.new
       else
         raise Error, "File #{file_name} not found"
@@ -405,7 +406,7 @@ module Zip
       tmpfile.close
       if yield tmp_filename
         ::File.rename(tmp_filename, name)
-        ::File.chmod(@exist_file_perms, name) if defined?(@exist_file_perms)
+        ::File.chmod(@file_permissions, name) if defined?(@file_permissions)
       end
     ensure
       tmpfile.unlink if tmpfile
@@ -416,6 +417,10 @@ module Zip
       temp_file.binmode
       temp_file
     end
+
+    def create_file_permissions
+      ::Zip::RUNNING_ON_WINDOWS ? 0644 : 0666 - ::File.umask
+    end
   end
 end
 
diff --git a/test/file_permissions_test.rb b/test/file_permissions_test.rb
new file mode 100644
index 0000000..67ae30b
--- /dev/null
+++ b/test/file_permissions_test.rb
@@ -0,0 +1,69 @@
+require 'test_helper'
+
+class FilePermissionsTest < MiniTest::Test
+
+  FILENAME = File.join(File.dirname(__FILE__), "umask.zip")
+
+  def teardown
+    ::File.unlink(FILENAME)
+  end
+
+  if ::Zip::RUNNING_ON_WINDOWS
+    # Windows tests
+
+    DEFAULT_PERMS = 0644
+
+    def test_windows_perms
+      create_file
+
+      assert_equal DEFAULT_PERMS, ::File.stat(FILENAME).mode
+    end
+
+  else
+    # Unix tests
+
+    DEFAULT_PERMS = 0100666
+
+    def test_current_umask
+      umask = DEFAULT_PERMS - ::File.umask
+      create_file
+
+      assert_equal umask, ::File.stat(FILENAME).mode
+    end
+
+    def test_umask_000
+      set_umask(0000) do
+        create_file
+      end
+
+      assert_equal DEFAULT_PERMS, ::File.stat(FILENAME).mode
+    end
+
+    def test_umask_066
+      umask = 0066
+      set_umask(umask) do
+        create_file
+      end
+
+      assert_equal((DEFAULT_PERMS - umask), ::File.stat(FILENAME).mode)
+    end
+
+  end
+
+  def create_file
+    ::Zip::File.open(FILENAME, ::Zip::File::CREATE) do |zip|
+      zip.comment = "test"
+    end
+  end
+
+  # If anything goes wrong, make sure the umask is restored.
+  def set_umask(umask, &block)
+    begin
+      saved_umask = ::File.umask(umask)
+      yield
+    ensure
+      ::File.umask(saved_umask)
+    end
+  end
+
+end