diff --git a/modules/pubmaticBidAdapter.js b/modules/pubmaticBidAdapter.js
index e9ae90bdc50..4502dc66a65 100644
--- a/modules/pubmaticBidAdapter.js
+++ b/modules/pubmaticBidAdapter.js
@@ -1044,6 +1044,13 @@ export const spec = {
                 newBid.meta.clickUrl = bid.adomain[0];
               }
 
+              // adserverTargeting
+              if (seatbidder.ext && seatbidder.ext.buyid) {
+                newBid.adserverTargeting = {
+                  'hb_buyid_pubmatic': seatbidder.ext.buyid
+                };
+              }
+
               bidResponses.push(newBid);
             });
         });
diff --git a/modules/pubmaticBidAdapter.md b/modules/pubmaticBidAdapter.md
index 4a5d881a637..a045bed3e2b 100644
--- a/modules/pubmaticBidAdapter.md
+++ b/modules/pubmaticBidAdapter.md
@@ -202,5 +202,7 @@ pbjs.setConfig({
 ```
 Note: Combine the above the configuration with any other UserSync configuration.  Multiple setConfig() calls overwrite each other and only last call for a given attribute will take effect. 
 
-Note: PubMatic will return a test-bid if "pubmaticTest=true" is present in page URL
+# Notes: 
+- PubMatic will return a test-bid if "pubmaticTest=true" is present in page URL
+- PubMatic will set bid.adserverTargeting.hb_buyid_pubmatic targeting key while submitting a bid into Prebid
 
diff --git a/test/spec/modules/pubmaticBidAdapter_spec.js b/test/spec/modules/pubmaticBidAdapter_spec.js
index d840d2527bd..817661ef51f 100644
--- a/test/spec/modules/pubmaticBidAdapter_spec.js
+++ b/test/spec/modules/pubmaticBidAdapter_spec.js
@@ -534,6 +534,9 @@ describe('PubMatic adapter', function () {
         'id': '93D3BAD6-E2E2-49FB-9D89-920B1761C865',
         'seatbid': [{
           'seat': 'seat-id',
+          'ext': {
+            'buyid': 'BUYER-ID-987'
+          },
           'bid': [{
             'id': '74858439-49D7-4169-BA5D-44A046315B2F',
             'impid': '22bddb28db77d',
@@ -549,6 +552,9 @@ describe('PubMatic adapter', function () {
             }
           }]
         }, {
+          'ext': {
+            'buyid': 'BUYER-ID-789'
+          },
           'bid': [{
             'id': '74858439-49D7-4169-BA5D-44A046315BEF',
             'impid': '22bddb28db77e',
@@ -2622,6 +2628,7 @@ describe('PubMatic adapter', function () {
         expect(response[0].netRevenue).to.equal(false);
         expect(response[0].ttl).to.equal(300);
         expect(response[0].meta.networkId).to.equal(123);
+        expect(response[0].adserverTargeting.hb_buyid_pubmatic).to.equal('BUYER-ID-987');
         expect(response[0].meta.buyerId).to.equal(976);
         expect(response[0].meta.clickUrl).to.equal('blackrock.com');
         expect(response[0].referrer).to.include(data.site.ref);
@@ -2643,6 +2650,7 @@ describe('PubMatic adapter', function () {
         expect(response[1].netRevenue).to.equal(false);
         expect(response[1].ttl).to.equal(300);
         expect(response[1].meta.networkId).to.equal(422);
+        expect(response[1].adserverTargeting.hb_buyid_pubmatic).to.equal('BUYER-ID-789');
         expect(response[1].meta.buyerId).to.equal(832);
         expect(response[1].meta.clickUrl).to.equal('hivehome.com');
         expect(response[1].referrer).to.include(data.site.ref);