diff --git a/changelog/+hfid_support_cardinality_many_relationships.changed.md b/changelog/+hfid_support_cardinality_many_relationships.changed.md
new file mode 100644
index 00000000..373120d2
--- /dev/null
+++ b/changelog/+hfid_support_cardinality_many_relationships.changed.md
@@ -0,0 +1 @@
+Set the HFID on related nodes for cardinality many relationships and add hfid support to the RelationshipManager add, extend and remove methods
diff --git a/infrahub_sdk/node.py b/infrahub_sdk/node.py
index 8628e7cc..6d8160f7 100644
--- a/infrahub_sdk/node.py
+++ b/infrahub_sdk/node.py
@@ -479,7 +479,7 @@ def _generate_query_data(cls, peer_data: dict[str, Any] | None = None, property:
         """
         data: dict[str, Any] = {
             "count": None,
-            "edges": {"node": {"id": None, "display_label": None, "__typename": None}},
+            "edges": {"node": {"id": None, "hfid": None, "display_label": None, "__typename": None}},
         }
 
         properties: dict[str, Any] = {}
@@ -569,7 +569,9 @@ def add(self, data: str | RelatedNode | dict) -> None:
             raise UninitializedError("Must call fetch() on RelationshipManager before editing members")
         new_node = RelatedNode(schema=self.schema, client=self.client, branch=self.branch, data=data)
 
-        if new_node.id and new_node.id not in self.peer_ids:
+        if (new_node.id and new_node.id not in self.peer_ids) or (
+            new_node.hfid and new_node.hfid not in self.peer_hfids
+        ):
             self.peers.append(new_node)
             self._has_update = True
 
@@ -591,6 +593,14 @@ def remove(self, data: str | RelatedNode | dict) -> None:
             self.peers.pop(idx)
             self._has_update = True
 
+        elif node_to_remove.hfid and node_to_remove.hfid in self.peer_hfids:
+            idx = self.peer_hfids.index(node_to_remove.hfid)
+            if self.peers[idx].hfid != node_to_remove.hfid:
+                raise IndexError(f"Unexpected situation, the node with the index {idx} should be {node_to_remove.hfid}")
+
+            self.peers.pop(idx)
+            self._has_update = True
+
 
 class RelationshipManagerSync(RelationshipManagerBase):
     """Manages relationships of a node in a synchronous context."""
@@ -664,7 +674,9 @@ def add(self, data: str | RelatedNodeSync | dict) -> None:
             raise UninitializedError("Must call fetch() on RelationshipManager before editing members")
         new_node = RelatedNodeSync(schema=self.schema, client=self.client, branch=self.branch, data=data)
 
-        if new_node.id and new_node.id not in self.peer_ids:
+        if (new_node.id and new_node.id not in self.peer_ids) or (
+            new_node.hfid and new_node.hfid not in self.peer_hfids
+        ):
             self.peers.append(new_node)
             self._has_update = True
 
@@ -682,6 +694,13 @@ def remove(self, data: str | RelatedNodeSync | dict) -> None:
             idx = self.peer_ids.index(node_to_remove.id)
             if self.peers[idx].id != node_to_remove.id:
                 raise IndexError(f"Unexpected situation, the node with the index {idx} should be {node_to_remove.id}")
+            self.peers.pop(idx)
+            self._has_update = True
+
+        elif node_to_remove.hfid and node_to_remove.hfid in self.peer_hfids:
+            idx = self.peer_hfids.index(node_to_remove.hfid)
+            if self.peers[idx].hfid != node_to_remove.hfid:
+                raise IndexError(f"Unexpected situation, the node with the index {idx} should be {node_to_remove.hfid}")
 
             self.peers.pop(idx)
             self._has_update = True
diff --git a/tests/unit/sdk/test_node.py b/tests/unit/sdk/test_node.py
index 70966f6a..fbe381bf 100644
--- a/tests/unit/sdk/test_node.py
+++ b/tests/unit/sdk/test_node.py
@@ -1105,6 +1105,7 @@ async def test_query_data_include_property(client, location_schema: NodeSchemaAP
                             },
                             "node": {
                                 "id": None,
+                                "hfid": None,
                                 "display_label": None,
                                 "__typename": None,
                             },
@@ -1157,6 +1158,7 @@ async def test_query_data_include(client, location_schema: NodeSchemaAPI, client
                         "edges": {
                             "node": {
                                 "id": None,
+                                "hfid": None,
                                 "display_label": None,
                                 "__typename": None,
                             },