diff --git a/ChangeLog b/ChangeLog
index 9c56a36b91..5fa0e44c81 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Oct 26 15:24:25 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* file.c (rb_file_join): honor input encodings than ASCII-8BIT.
+	  [ruby-core:40338] [Bug #5483]
+
 Tue Oct 25 21:52:31 2011  Tanaka Akira  <akr@fsij.org>
 
 	* include/ruby/defines.h: use "__sparc" instead of "sparc" and
diff --git a/file.c b/file.c
index bd96ffee35..3107895037 100644
--- a/file.c
+++ b/file.c
@@ -3847,7 +3847,10 @@ rb_file_join(VALUE ary, VALUE sep)
 	    FilePathStringValue(tmp);
 	}
 	name = StringValueCStr(result);
-	if (i > 0 && !NIL_P(sep)) {
+	if (i == 0) {
+	    rb_enc_copy(result, tmp);
+	}
+	else if (!NIL_P(sep)) {
 	    tail = chompdirsep(name);
 	    if (RSTRING_PTR(tmp) && isdirsep(RSTRING_PTR(tmp)[0])) {
 		rb_str_set_len(result, tail - name);
diff --git a/test/ruby/test_path.rb b/test/ruby/test_path.rb
index 74d568ae49..2db7be0b76 100644
--- a/test/ruby/test_path.rb
+++ b/test/ruby/test_path.rb
@@ -247,4 +247,13 @@ class TestPath < Test::Unit::TestCase
     assert_raise(Encoding::CompatibilityError) {open(s.encode("utf-32be"))}
     assert_raise(Encoding::CompatibilityError) {open(s.encode("utf-32le"))}
   end
+
+  def test_join
+    bug5483 = '[ruby-core:40338]'
+    path = %w[a b]
+    Encoding.list.each do |e|
+      next unless e.ascii_compatible?
+      assert_equal(e, File.join(*path.map {|s| s.force_encoding(e)}).encoding, bug5483)
+    end
+  end
 end