diff --git a/io.c b/io.c
index cb24b283d2..ebf5743d37 100644
--- a/io.c
+++ b/io.c
@@ -1678,7 +1678,7 @@ io_writev(int argc, VALUE *argv, VALUE io)
 static VALUE
 io_write_m(int argc, VALUE *argv, VALUE io)
 {
-    if (argc > 1) {
+    if (argc != 1) {
 	return io_writev(argc, argv, io);
     }
     else {
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index a271c9e677..43c3ed7566 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1287,6 +1287,13 @@ class TestIO < Test::Unit::TestCase
     assert_empty(err)
   end
 
+  def test_write_no_args
+    IO.pipe do |r, w|
+      assert_equal 0, w.write, '[ruby-core:86285] [Bug #14338]'
+      assert_equal :wait_readable, r.read_nonblock(1, exception: false)
+    end
+  end
+
   def test_write_non_writable
     with_pipe do |r, w|
       assert_raise(IOError) do