diff --git a/components/script/dom/htmlserializer.rs b/components/script/dom/htmlserializer.rs
index 07c5b3d71219..9e84900a9c0b 100644
--- a/components/script/dom/htmlserializer.rs
+++ b/components/script/dom/htmlserializer.rs
@@ -93,9 +93,9 @@ fn serialize_text(text: JSRef<Text>, html: &mut String) {
 fn serialize_processing_instruction(processing_instruction: JSRef<ProcessingInstruction>,
                                     html: &mut String) {
     html.push_str("<?");
-    html.push_str(processing_instruction.target.as_slice());
+    html.push_str(processing_instruction.target().as_slice());
     html.push_char(' ');
-    html.push_str(processing_instruction.characterdata.data().as_slice());
+    html.push_str(processing_instruction.characterdata().data().as_slice());
     html.push_str("?>");
 }
 
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index 8a2179a07601..68119f33d231 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -1496,8 +1496,8 @@ impl Node {
             },
             ProcessingInstructionNodeTypeId => {
                 let pi: JSRef<ProcessingInstruction> = ProcessingInstructionCast::to_ref(node).unwrap();
-                let pi = ProcessingInstruction::new(pi.target.clone(),
-                                                    pi.characterdata.data().clone(), *document);
+                let pi = ProcessingInstruction::new(pi.target().clone(),
+                                                    pi.characterdata().data().clone(), *document);
                 NodeCast::from_temporary(pi)
             },
         }.root();
@@ -1974,8 +1974,8 @@ impl<'a> NodeMethods for JSRef<'a, Node> {
         fn is_equal_processinginstruction(node: JSRef<Node>, other: JSRef<Node>) -> bool {
             let pi: JSRef<ProcessingInstruction> = ProcessingInstructionCast::to_ref(node).unwrap();
             let other_pi: JSRef<ProcessingInstruction> = ProcessingInstructionCast::to_ref(other).unwrap();
-            (pi.target == other_pi.target) &&
-            (*pi.characterdata.data() == *other_pi.characterdata.data())
+            (*pi.target() == *other_pi.target()) &&
+            (*pi.characterdata().data() == *other_pi.characterdata().data())
         }
         fn is_equal_characterdata(node: JSRef<Node>, other: JSRef<Node>) -> bool {
             let characterdata: JSRef<CharacterData> = CharacterDataCast::to_ref(node).unwrap();
diff --git a/components/script/dom/processinginstruction.rs b/components/script/dom/processinginstruction.rs
index ed5c9522aa04..19017ae90506 100644
--- a/components/script/dom/processinginstruction.rs
+++ b/components/script/dom/processinginstruction.rs
@@ -16,9 +16,10 @@ use servo_util::str::DOMString;
 /// An HTML processing instruction node.
 #[jstraceable]
 #[must_root]
+#[privatize]
 pub struct ProcessingInstruction {
-    pub characterdata: CharacterData,
-    pub target: DOMString,
+    characterdata: CharacterData,
+    target: DOMString,
 }
 
 impl ProcessingInstructionDerived for EventTarget {
@@ -39,6 +40,14 @@ impl ProcessingInstruction {
         Node::reflect_node(box ProcessingInstruction::new_inherited(target, data, document),
                            document, ProcessingInstructionBinding::Wrap)
     }
+
+    pub fn characterdata<'a>(&'a self) -> &'a CharacterData {
+        &self.characterdata
+    }
+
+    pub fn target<'a>(&'a self) -> &'a DOMString {
+        &self.target
+    }
 }
 
 impl<'a> ProcessingInstructionMethods for JSRef<'a, ProcessingInstruction> {