diff --git a/ChangeLog b/ChangeLog
index f09329e55e..8c7bb4e977 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Mar  9 09:19:55 2016  Rei Odaira  <Rei.Odaira@gmail.com>
+
+	* test/io/wait/test_io_wait.rb (test_wait_readwrite_timeout):
+	  select(2) in AIX returns "readable" for the write-side fd
+	  of a pipe, so it is not possible to use a pipe to test
+	  the read-write timeout of IO#wait on AIX.
+
 Wed Mar  9 03:35:22 2016  Charles Oliver Nutter  <headius@headius.com>
 
 	* test/ruby/test_require.rb (test_require_with_loaded_features_pop):
diff --git a/test/io/wait/test_io_wait.rb b/test/io/wait/test_io_wait.rb
index 6c6fd83116..2c1073d104 100644
--- a/test/io/wait/test_io_wait.rb
+++ b/test/io/wait/test_io_wait.rb
@@ -141,7 +141,14 @@ class TestIOWait < Test::Unit::TestCase
   def test_wait_readwrite_timeout
     assert_equal @w, @w.wait(0.01, :read_write)
     written = fill_pipe
-    assert_nil @w.wait(0.01, :read_write)
+    if /aix/ =~ RUBY_PLATFORM
+      # IO#wait internally uses select(2) on AIX.
+      # AIX's select(2) returns "readable" for the write-side fd
+      # of a pipe, so @w.wait(0.01, :read_write) does not return nil.
+      assert_equal @w, @w.wait(0.01, :read_write)
+    else
+      assert_nil @w.wait(0.01, :read_write)
+    end
     @r.read(written)
     assert_equal @w, @w.wait(0.01, :read_write)
   end