diff --git a/modules/conversantBidAdapter.js b/modules/conversantBidAdapter.js
index cb0661c4417..90865493d8d 100644
--- a/modules/conversantBidAdapter.js
+++ b/modules/conversantBidAdapter.js
@@ -99,7 +99,9 @@ export const spec = {
         imp.banner = banner;
       }
 
-      if (bid.crumbs && bid.crumbs.pubcid) {
+      if (bid.userId && bid.userId.pubcid) {
+        pubcid = bid.userId.pubcid;
+      } else if (bid.crumbs && bid.crumbs.pubcid) {
         pubcid = bid.crumbs.pubcid;
       }
 
diff --git a/test/spec/modules/conversantBidAdapter_spec.js b/test/spec/modules/conversantBidAdapter_spec.js
index 34991252fa8..bfe3c6e8fa1 100644
--- a/test/spec/modules/conversantBidAdapter_spec.js
+++ b/test/spec/modules/conversantBidAdapter_spec.js
@@ -375,6 +375,19 @@ describe('Conversant adapter tests', function() {
     expect(payload).to.have.deep.nested.property('user.ext.fpc', 12345);
   });
 
+  it('Verify User ID publisher commond id support', function() {
+    // clone bidRequests
+    let requests = utils.deepClone(bidRequests)
+
+    // add pubcid to every entry
+    requests.forEach((unit) => {
+      Object.assign(unit, {userId: {pubcid: 67890}});
+    });
+    //  construct http post payload
+    const payload = spec.buildRequests(requests).data;
+    expect(payload).to.have.deep.nested.property('user.ext.fpc', 67890);
+  });
+
   it('Verify GDPR bid request', function() {
     // add gdpr info
     const bidRequest = {