diff --git a/io.c b/io.c
index f78c09ba40..d0257ff42e 100644
--- a/io.c
+++ b/io.c
@@ -10312,6 +10312,12 @@ rb_io_s_pipe(int argc, VALUE *argv, VALUE klass)
     rb_io_synchronized(fptr2);
 
     extract_binmode(opt, &fmode);
+
+    if ((fmode & FMODE_BINMODE) && v1 == Qnil) {
+	rb_io_ascii8bit_binmode(r);
+	rb_io_ascii8bit_binmode(w);
+    }
+
 #if DEFAULT_TEXTMODE
     if ((fptr->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
 	fptr->mode &= ~FMODE_TEXTMODE;
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 0c81f4cb82..4a7866162a 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -113,6 +113,54 @@ def test_pipe
     ].each{|thr| thr.join}
   end
 
+  def test_binmode_pipe
+    EnvUtil.with_default_internal(Encoding::UTF_8) do
+      EnvUtil.with_default_external(Encoding::UTF_8) do
+        reader, writer = IO.pipe
+        reader.binmode
+        writer.binmode
+
+        reader1, writer1 = IO.pipe
+
+        reader2, writer2 = IO.pipe(binmode: true)
+        assert writer.binmode?
+        assert writer2.binmode?
+        assert_equal writer.binmode?, writer2.binmode?
+        assert_equal writer.external_encoding, writer2.external_encoding
+        assert_equal writer.internal_encoding, writer2.internal_encoding
+        assert reader.binmode?
+        assert reader2.binmode?
+        assert_equal reader.binmode?, reader2.binmode?
+        assert_equal reader.external_encoding, reader2.external_encoding
+        assert_equal reader.internal_encoding, reader2.internal_encoding
+
+        reader3, writer3 = IO.pipe("UTF-8:UTF-8", binmode: true)
+        assert writer3.binmode?
+        assert_equal writer1.external_encoding, writer3.external_encoding
+        assert_equal writer1.internal_encoding, writer3.internal_encoding
+        assert reader3.binmode?
+        assert_equal reader1.external_encoding, reader3.external_encoding
+        assert_equal reader1.internal_encoding, reader3.internal_encoding
+
+        reader4, writer4 = IO.pipe("UTF-8:UTF-8", binmode: true)
+        assert writer4.binmode?
+        assert_equal writer1.external_encoding, writer4.external_encoding
+        assert_equal writer1.internal_encoding, writer4.internal_encoding
+        assert reader4.binmode?
+        assert_equal reader1.external_encoding, reader4.external_encoding
+        assert_equal reader1.internal_encoding, reader4.internal_encoding
+
+        reader5, writer5 = IO.pipe("UTF-8", "UTF-8", binmode: true)
+        assert writer5.binmode?
+        assert_equal writer1.external_encoding, writer5.external_encoding
+        assert_equal writer1.internal_encoding, writer5.internal_encoding
+        assert reader5.binmode?
+        assert_equal reader1.external_encoding, reader5.external_encoding
+        assert_equal reader1.internal_encoding, reader5.internal_encoding
+      end
+    end
+  end
+
   def test_pipe_block
     x = nil
     ret = IO.pipe {|r, w|