diff --git a/modules/stroeerCoreBidAdapter.js b/modules/stroeerCoreBidAdapter.js
index ff20ed5deed..0a16607d621 100644
--- a/modules/stroeerCoreBidAdapter.js
+++ b/modules/stroeerCoreBidAdapter.js
@@ -221,7 +221,7 @@ export const spec = {
       };
     }
 
-    const ORTB2_KEYS = ['regs.ext.dsa', 'device.ext.cdep', 'source.tid'];
+    const ORTB2_KEYS = ['regs.ext.dsa', 'device.ext.cdep', 'source.tid', 'site.ext'];
     ORTB2_KEYS.forEach(key => {
       const value = utils.deepAccess(bidderRequest.ortb2, key);
       if (value !== undefined) {
diff --git a/test/spec/modules/stroeerCoreBidAdapter_spec.js b/test/spec/modules/stroeerCoreBidAdapter_spec.js
index ab23cff77d8..cae45720717 100644
--- a/test/spec/modules/stroeerCoreBidAdapter_spec.js
+++ b/test/spec/modules/stroeerCoreBidAdapter_spec.js
@@ -1350,6 +1350,28 @@ describe('stroeerCore bid adapter', function() {
 
           assert.deepEqual(sentOrtb2, ortb2);
         });
+
+        it('should add the ortb2 site extension', () => {
+          const bidReq = buildBidderRequest();
+
+          const ortb2 = {
+            site: {
+              domain: 'example.com',
+              ext: {
+                data: {
+                  abc: '123'
+                }
+              }
+            }
+          };
+
+          bidReq.ortb2 = utils.deepClone(ortb2);
+
+          const serverRequestInfo = spec.buildRequests(bidReq.bids, bidReq)[0];
+
+          const sentOrtb2 = serverRequestInfo.data.ortb2;
+          assert.deepEqual(sentOrtb2, {site: {ext: ortb2.site.ext}})
+        });
       });
 
       describe('Split bid requests', () => {