diff --git a/src/lib.rs b/src/lib.rs
index da1af26c..06048c8e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -194,3 +194,6 @@ pub mod eme;
 
 /// XEP-0390: Entity Capabilities 2.0
 pub mod ecaps2;
+
+/// XEP-0421: Anonymous unique occupant identifiers for MUCs
+pub mod occupant_id;
diff --git a/src/ns.rs b/src/ns.rs
index f5941258..ef785082 100644
--- a/src/ns.rs
+++ b/src/ns.rs
@@ -204,6 +204,9 @@ pub const ECAPS2: &str = "urn:xmpp:caps";
 /// XEP-0390: Entity Capabilities 2.0
 pub const ECAPS2_OPTIMIZE: &str = "urn:xmpp:caps:optimize";
 
+/// XEP-0421: Anonymous unique occupant identifiers for MUCs
+pub const OID: &str = "urn:xmpp:occupant-id:0";
+
 /// Alias for the main namespace of the stream, that is "jabber:client" when
 /// the component feature isn’t enabled.
 #[cfg(not(feature = "component"))]
diff --git a/src/occupant_id.rs b/src/occupant_id.rs
new file mode 100644
index 00000000..73065294
--- /dev/null
+++ b/src/occupant_id.rs
@@ -0,0 +1,89 @@
+// Copyright (c) 2019 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+use crate::message::MessagePayload;
+use crate::presence::PresencePayload;
+
+generate_element!(
+    /// Unique identifier given to a MUC participant.
+    ///
+    /// It allows clients to identify a MUC participant across reconnects and
+    /// renames. It thus prevents impersonification of anonymous users.
+    OccupantId, "occupant-id", OID,
+
+    attributes: [
+        /// The id associated to the sending user by the MUC service.
+        id: Required<String> = "id",
+    ]
+);
+
+impl MessagePayload for OccupantId {}
+impl PresencePayload for OccupantId {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::util::error::Error;
+    use minidom::Element;
+    use std::convert::TryFrom;
+
+    #[cfg(target_pointer_width = "32")]
+    #[test]
+    fn test_size() {
+        assert_size!(OccupantId, 12);
+    }
+
+    #[cfg(target_pointer_width = "64")]
+    #[test]
+    fn test_size() {
+        assert_size!(OccupantId, 24);
+    }
+
+    #[test]
+    fn test_simple() {
+        let elem: Element = "<occupant-id xmlns='urn:xmpp:occupant-id:0' id='coucou'/>"
+            .parse()
+            .unwrap();
+        let origin_id = OccupantId::try_from(elem).unwrap();
+        assert_eq!(origin_id.id, "coucou");
+    }
+
+    #[test]
+    fn test_invalid_child() {
+        let elem: Element = "<occupant-id xmlns='urn:xmpp:occupant-id:0'><coucou/></occupant-id>"
+            .parse()
+            .unwrap();
+        let error = OccupantId::try_from(elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "Unknown child in occupant-id element.");
+    }
+
+    #[test]
+    fn test_invalid_id() {
+        let elem: Element = "<occupant-id xmlns='urn:xmpp:occupant-id:0'/>".parse().unwrap();
+        let error = OccupantId::try_from(elem).unwrap_err();
+        let message = match error {
+            Error::ParseError(string) => string,
+            _ => panic!(),
+        };
+        assert_eq!(message, "Required attribute 'id' missing.");
+    }
+
+    #[test]
+    fn test_serialise() {
+        let elem: Element = "<occupant-id xmlns='urn:xmpp:occupant-id:0' id='coucou'/>"
+            .parse()
+            .unwrap();
+        let occupant_id = OccupantId {
+            id: String::from("coucou"),
+        };
+        let elem2 = occupant_id.into();
+        assert_eq!(elem, elem2);
+    }
+}