diff --git a/src/serialize/mod.rs b/src/serialize/mod.rs
index dc81424f..1b6d1759 100644
--- a/src/serialize/mod.rs
+++ b/src/serialize/mod.rs
@@ -191,4 +191,12 @@ impl<'wr, Wr: Writer> Serializer<'wr, Wr> {
         try!(self.writer.write_str(name));
         self.writer.write_char('\n')
     }
+
+    pub fn write_processing_instruction(&mut self, target: &str, data: &str) -> IoResult<()> {
+        try!(self.writer.write_str("<?"));
+        try!(self.writer.write_str(target));
+        try!(self.writer.write_char(' '));
+        try!(self.writer.write_str(data));
+        self.writer.write_char('>')
+    }
 }