diff --git a/middleware/dedupe.js b/middleware/dedupe.js
index 115b82a03..dacd0b055 100644
--- a/middleware/dedupe.js
+++ b/middleware/dedupe.js
@@ -113,6 +113,9 @@ function isPreferred(existingHit, candidateHit) {
   // https://github.com/pelias/api/issues/872
   if( !_.has(existingHit, 'address_parts.zip') &&
        _.has(candidateHit, 'address_parts.zip') ){ return true; }
+  // if the existing hit HAS a postcode, and this candidate does NOT, keep the existing hit
+  if( _.has(existingHit, 'address_parts.zip') &&
+       !_.has(candidateHit, 'address_parts.zip') ){ return false; }
 
   // prefer non-canonical sources over canonical ones
   if( !_.includes(canonical_sources, candidateHit.source) &&
diff --git a/test/unit/middleware/dedupe.js b/test/unit/middleware/dedupe.js
index fbe7014e3..92fd3443b 100644
--- a/test/unit/middleware/dedupe.js
+++ b/test/unit/middleware/dedupe.js
@@ -396,6 +396,42 @@ module.exports.tests.priority = function(test, common) {
     });
   });
 
+  test('osm with zip takes priority over openaddresses without zip, regardless of order of results', function (t) {
+    var req = {
+      clean: {
+        text: '100 Main St',
+        size: 100
+      }
+    };
+    var res = {
+      data:  [
+        {
+          'name': { 'default': '100 Main St' },
+          'source': 'openstreetmap',
+          'source_id': '654321',
+          'layer': 'address',
+          'address_parts': {
+            'zip': '54321'
+          }
+        },
+        {
+          'name': { 'default': '100 Main St' },
+          'source': 'openaddresses',
+          'source_id': '123456',
+          'layer': 'address',
+          'address_parts': {}
+        },
+      ]
+    };
+
+    var expectedCount = 1;
+    dedupe(req, res, function () {
+      t.equal(res.data.length, expectedCount, 'results have fewer items than before');
+      t.deepEqual(res.data[0].source_id, '654321', 'openstreetmap result with zip won');
+      t.end();
+    });
+  });
+
   test('works with name aliases', function (t) {
     var req = {
       clean: {