diff --git a/modules/adformBidAdapter.js b/modules/adformBidAdapter.js
index bf30a32b565..48000e082b2 100644
--- a/modules/adformBidAdapter.js
+++ b/modules/adformBidAdapter.js
@@ -20,6 +20,7 @@ export const spec = {
   buildRequests: function (validBidRequests, bidderRequest) {
     var i, l, j, k, bid, _key, _value, reqParams, netRevenue, gdprObject;
     const currency = config.getConfig('currency.adServerCurrency');
+    const eids = getEncodedEIDs(utils.deepAccess(validBidRequests, '0.userIdAsEids'));
 
     var request = [];
     var globalParams = [ [ 'adxDomain', 'adx.adform.net' ], [ 'fd', 1 ], [ 'url', null ], [ 'tid', null ] ];
@@ -64,6 +65,10 @@ export const spec = {
       request.push('us_privacy=' + bidderRequest.uspConsent);
     }
 
+    if (eids) {
+      request.push('eids=' + eids);
+    }
+
     for (i = 1, l = globalParams.length; i < l; i++) {
       _key = globalParams[i][0];
       _value = globalParams[i][1];
@@ -91,6 +96,28 @@ export const spec = {
 
       return encodeURIComponent(btoa(url.join('').slice(0, -1)));
     }
+
+    function getEncodedEIDs(eids) {
+      if (utils.isArray(eids) && eids.length > 0) {
+        const parsed = parseEIDs(eids);
+        return encodeURIComponent(btoa(JSON.stringify(parsed)));
+      }
+    }
+
+    function parseEIDs(eids) {
+      return eids.reduce((result, eid) => {
+        const source = eid.source;
+        result[source] = result[source] || {};
+
+        eid.uids.forEach(value => {
+          const id = value.id + '';
+          result[source][id] = result[source][id] || [];
+          result[source][id].push(value.atype);
+        });
+
+        return result;
+      }, {});
+    }
   },
   interpretResponse: function (serverResponse, bidRequest) {
     const VALID_RESPONSES = {
diff --git a/modules/adformOpenRTBBidAdapter.js b/modules/adformOpenRTBBidAdapter.js
index 300cb211dcf..3270fb5865a 100644
--- a/modules/adformOpenRTBBidAdapter.js
+++ b/modules/adformOpenRTBBidAdapter.js
@@ -61,6 +61,7 @@ export const spec = {
     const siteId = setOnAny(validBidRequests, 'params.siteId');
     const currency = config.getConfig('currency.adServerCurrency');
     const cur = currency && [ currency ];
+    const eids = setOnAny(validBidRequests, 'userIdAsEids');
 
     const imp = validBidRequests.map((bid, id) => {
       bid.netRevenue = pt;
@@ -133,6 +134,10 @@ export const spec = {
       utils.deepSetValue(request, 'regs.ext.us_privacy', bidderRequest.uspConsent);
     }
 
+    if (eids) {
+      utils.deepSetValue(request, 'user.ext.eids', eids);
+    }
+
     return {
       method: 'POST',
       url: 'https://' + adxDomain + '/adx/openrtb',
diff --git a/test/spec/modules/adformBidAdapter_spec.js b/test/spec/modules/adformBidAdapter_spec.js
index 5bf0576362c..360979659de 100644
--- a/test/spec/modules/adformBidAdapter_spec.js
+++ b/test/spec/modules/adformBidAdapter_spec.js
@@ -2,6 +2,7 @@ import {assert, expect} from 'chai';
 import {spec} from 'modules/adformBidAdapter.js';
 import { BANNER, VIDEO } from 'src/mediaTypes.js';
 import { config } from 'src/config.js';
+import { createEidsArray } from 'modules/userId/eids.js';
 
 describe('Adform adapter', function () {
   let serverResponse, bidRequest, bidResponses;
@@ -129,6 +130,25 @@ describe('Adform adapter', function () {
       assert.equal(parsedUrl.query.pt, 'gross');
     });
 
+    it('should pass extended ids', function () {
+      bids[0].userIdAsEids = createEidsArray({
+        tdid: 'TTD_ID_FROM_USER_ID_MODULE',
+        pubcid: 'pubCommonId_FROM_USER_ID_MODULE'
+      });
+      let request = spec.buildRequests(bids);
+      let eids = parseUrl(request.url).query.eids;
+
+      assert.equal(eids, 'eyJhZHNlcnZlci5vcmciOnsiVFREX0lEX0ZST01fVVNFUl9JRF9NT0RVTEUiOlsxXX0sInB1YmNpZC5vcmciOnsicHViQ29tbW9uSWRfRlJPTV9VU0VSX0lEX01PRFVMRSI6WzFdfX0%3D');
+      assert.deepEqual(JSON.parse(atob(decodeURIComponent(eids))), {
+        'adserver.org': {
+          'TTD_ID_FROM_USER_ID_MODULE': [1]
+        },
+        'pubcid.org': {
+          'pubCommonId_FROM_USER_ID_MODULE': [1]
+        }
+      });
+    });
+
     describe('user privacy', function () {
       it('should send GDPR Consent data to adform if gdprApplies', function () {
         let request = spec.buildRequests([bids[0]], {gdprConsent: {gdprApplies: true, consentString: 'concentDataString'}});
diff --git a/test/spec/modules/adformOpenRTBBidAdapter_spec.js b/test/spec/modules/adformOpenRTBBidAdapter_spec.js
index 9f21a9af756..05788183e29 100644
--- a/test/spec/modules/adformOpenRTBBidAdapter_spec.js
+++ b/test/spec/modules/adformOpenRTBBidAdapter_spec.js
@@ -3,6 +3,7 @@ import {assert, expect} from 'chai';
 import {spec} from 'modules/adformOpenRTBBidAdapter.js';
 import { NATIVE } from 'src/mediaTypes.js';
 import { config } from 'src/config.js';
+import { createEidsArray } from 'modules/userId/eids.js';
 
 describe('AdformOpenRTB adapter', function () {
   let serverResponse, bidRequest, bidResponses;
@@ -166,6 +167,23 @@ describe('AdformOpenRTB adapter', function () {
       });
     });
 
+    it('should pass extended ids', function () {
+      let validBidRequests = [{
+        bidId: 'bidId',
+        params: {},
+        userIdAsEids: createEidsArray({
+          tdid: 'TTD_ID_FROM_USER_ID_MODULE',
+          pubcid: 'pubCommonId_FROM_USER_ID_MODULE'
+        })
+      }];
+
+      let request = JSON.parse(spec.buildRequests(validBidRequests, { refererInfo: { referer: 'page' } }).data);
+      assert.deepEqual(request.user.ext.eids, [
+        { source: 'adserver.org', uids: [ { id: 'TTD_ID_FROM_USER_ID_MODULE', atype: 1, ext: { rtiPartner: 'TDID' } } ] },
+        { source: 'pubcid.org', uids: [ { id: 'pubCommonId_FROM_USER_ID_MODULE', atype: 1 } ] }
+      ]);
+    });
+
     it('should send currency if defined', function () {
       config.setConfig({ currency: { adServerCurrency: 'EUR' } });
       let validBidRequests = [{ params: {} }];