diff --git a/modules/actions/merge_polygon.js b/modules/actions/merge_polygon.js
index 8d5829401..0f29cd5b5 100644
--- a/modules/actions/merge_polygon.js
+++ b/modules/actions/merge_polygon.js
@@ -1,6 +1,6 @@
 import { geoPolygonContainsPolygon } from '../geo';
 import { osmJoinWays, osmRelation } from '../osm';
-import { utilArrayGroupBy, utilArrayIntersection, utilObjectOmit } from '../util';
+import { utilArrayGroupBy, utilArrayIntersection, utilObjectOmit, utilOldestID } from '../util';
 
 
 export function actionMergePolygon(ids, newRelationId) {
@@ -85,13 +85,21 @@ export function actionMergePolygon(ids, newRelationId) {
             outer = !outer;
         }
 
-        // Move all tags to one relation
-        var relation = entities.multipolygon[0] ||
-            osmRelation({ id: newRelationId, tags: { type: 'multipolygon' }});
+        // Move all tags to one relation.
+        // Keep the oldest multipolygon alive if it exists.
+        var relation;
+        if (entities.multipolygon.length > 0) {
+            var oldestID = utilOldestID(entities.multipolygon.map((entity) => entity.id));
+            relation = entities.multipolygon.find((entity) => entity.id === oldestID);
+        } else {
+            relation = osmRelation({ id: newRelationId, tags: { type: 'multipolygon' }});
+        }
 
-        entities.multipolygon.slice(1).forEach(function(m) {
-            relation = relation.mergeTags(m.tags);
-            graph = graph.remove(m);
+        entities.multipolygon.forEach(function(m) {
+            if (m.id !== relation.id) {
+                relation = relation.mergeTags(m.tags);
+                graph = graph.remove(m);
+            }
         });
 
         entities.closedWay.forEach(function(way) {
diff --git a/test/spec/actions/merge_polygon.js b/test/spec/actions/merge_polygon.js
index d3f7e0f4f..89814da98 100644
--- a/test/spec/actions/merge_polygon.js
+++ b/test/spec/actions/merge_polygon.js
@@ -68,15 +68,15 @@ describe('iD.actionMergePolygon', function () {
         expect(r.members.length).to.equal(3);
     });
 
-    it('creates a multipolygon from two multipolygon relations', function() {
-        graph = iD.actionMergePolygon(['w0', 'w1'], 'r')(graph);
-        graph = iD.actionMergePolygon(['w2', 'w5'], 'r2')(graph);
-        graph = iD.actionMergePolygon(['r', 'r2'])(graph);
+    it('creates a multipolygon from two multipolygon relations and keeps the oldest alive', function() {
+        graph = iD.actionMergePolygon(['w0', 'w1'], 'r2')(graph);
+        graph = iD.actionMergePolygon(['w2', 'w5'], 'r1')(graph);
+        graph = iD.actionMergePolygon(['r2', 'r1'])(graph);
 
         // Delete other relation
         expect(graph.hasEntity('r2')).to.equal(undefined);
 
-        var r = graph.entity('r');
+        var r = graph.entity('r1');
         expect(find(r, 'w0').role).to.equal('outer');
         expect(find(r, 'w1').role).to.equal('inner');
         expect(find(r, 'w2').role).to.equal('outer');