diff --git a/modules/33acrossBidAdapter.js b/modules/33acrossBidAdapter.js
index 07773ebe999..5df2af7f32e 100644
--- a/modules/33acrossBidAdapter.js
+++ b/modules/33acrossBidAdapter.js
@@ -5,6 +5,8 @@ import * as utils from '../src/utils.js';
 const BIDDER_CODE = '33across';
 const END_POINT = 'https://ssc.33across.com/api/v1/hb';
 const SYNC_ENDPOINT = 'https://ssc-cms.33across.com/ps/?m=xch&rt=html&ru=deb';
+const MEDIA_TYPE = 'banner';
+const CURRENCY = 'USD';
 
 const adapterState = {
   uniqueSiteIds: []
@@ -67,11 +69,27 @@ function _getAdSlotHTMLElement(adUnitCode) {
 
 // Infer the necessary data from valid bid for a minimal ttxRequest and create HTTP request
 // NOTE: At this point, TTX only accepts request for a single impression
-function _createServerRequest(bidRequest, gdprConsent = {}, uspConsent, pageUrl) {
+function _createServerRequest({bidRequest, gdprConsent = {}, uspConsent, pageUrl}) {
   const ttxRequest = {};
   const params = bidRequest.params;
   const element = _getAdSlotHTMLElement(bidRequest.adUnitCode);
   const sizes = _transformSizes(bidRequest.sizes);
+
+  let format;
+
+  // We support size based bidfloors so obtain one if there's a rule associated
+  if (typeof bidRequest.getFloor === 'function') {
+    let getFloor = bidRequest.getFloor.bind(bidRequest);
+
+    format = sizes.map((size) => {
+      const formatExt = _getBidFloors(getFloor, size);
+
+      return Object.assign({}, size, formatExt);
+    });
+  } else {
+    format = sizes;
+  }
+
   const minSize = _getMinSize(sizes);
 
   const viewabilityAmount = _isViewabilityMeasurable(element)
@@ -86,7 +104,7 @@ function _createServerRequest(bidRequest, gdprConsent = {}, uspConsent, pageUrl)
   ttxRequest.imp = [];
   ttxRequest.imp[0] = {
     banner: {
-      format: sizes
+      format
     },
     ext: {
       ttx: {
@@ -179,6 +197,24 @@ function _createSync({ siteId = 'zzz000000000003zzz', gdprConsent = {}, uspConse
   return sync;
 }
 
+function _getBidFloors(getFloor, size) {
+  const bidFloors = getFloor({
+    currency: CURRENCY,
+    mediaType: MEDIA_TYPE,
+    size: [ size.w, size.h ]
+  });
+
+  if (!isNaN(bidFloors.floor) && (bidFloors.currency === CURRENCY)) {
+    return {
+      ext: {
+        ttx: {
+          bidfloors: [ bidFloors.floor ]
+        }
+      }
+    }
+  }
+}
+
 function _getSize(size) {
   return {
     w: parseInt(size[0], 10),
@@ -320,7 +356,14 @@ function buildRequests(bidRequests, bidderRequest) {
 
   adapterState.uniqueSiteIds = bidRequests.map(req => req.params.siteId).filter(utils.uniques);
 
-  return bidRequests.map(req => _createServerRequest(req, gdprConsent, uspConsent, pageUrl));
+  return bidRequests.map(bidRequest => _createServerRequest(
+    {
+      bidRequest,
+      gdprConsent,
+      uspConsent,
+      pageUrl
+    })
+  );
 }
 
 // NOTE: At this point, the response from 33exchange will only ever contain one bid i.e. the highest bid
diff --git a/test/spec/modules/33acrossBidAdapter_spec.js b/test/spec/modules/33acrossBidAdapter_spec.js
index 0e67b7efb63..3721cef18d9 100644
--- a/test/spec/modules/33acrossBidAdapter_spec.js
+++ b/test/spec/modules/33acrossBidAdapter_spec.js
@@ -140,6 +140,22 @@ describe('33acrossBidAdapter:', function () {
       return this;
     };
 
+    this.withFormatFloors = floors => {
+      const format = ttxRequest.imp[0].banner.format.map((fm, i) => {
+        return Object.assign(fm, {
+          ext: {
+            ttx: {
+              bidfloors: [ floors[i] ]
+            }
+          }
+        })
+      });
+
+      ttxRequest.imp[0].banner.format = format;
+
+      return this;
+    };
+
     this.build = () => ttxRequest;
   }
 
@@ -667,6 +683,57 @@ describe('33acrossBidAdapter:', function () {
         expect(builtServerRequests).to.deep.equal([serverRequest]);
       });
     });
+
+    context('when price floor module is not enabled in bidRequest', function() {
+      it('does not set any bidfloors in ttxRequest', function() {
+        const ttxRequest = new TtxRequestBuilder()
+          .build();
+        const serverRequest = new ServerRequestBuilder()
+          .withData(ttxRequest)
+          .build();
+        const builtServerRequests = spec.buildRequests(bidRequests, {});
+
+        expect(builtServerRequests).to.deep.equal([serverRequest]);
+      });
+    });
+
+    context('when price floor module is enabled in bidRequest', function() {
+      it('does not set any bidfloors in ttxRequest if there is no floor', function() {
+        bidRequests[0].getFloor = () => ({});
+
+        const ttxRequest = new TtxRequestBuilder()
+          .build();
+        const serverRequest = new ServerRequestBuilder()
+          .withData(ttxRequest)
+          .build();
+        const builtServerRequests = spec.buildRequests(bidRequests, {});
+
+        expect(builtServerRequests).to.deep.equal([serverRequest]);
+      });
+
+      it('sets bidfloors in ttxRequest if there is a floor', function() {
+        bidRequests[0].getFloor = ({size, currency, mediaType}) => {
+          const floor = (size[0] === 300 && size[1] === 250) ? 1.0 : 0.10
+          return (
+            {
+              floor,
+              currency: 'USD'
+            }
+          );
+        };
+
+        const ttxRequest = new TtxRequestBuilder()
+          .withFormatFloors([ 1.0, 0.10 ])
+          .build();
+
+        const serverRequest = new ServerRequestBuilder()
+          .withData(ttxRequest)
+          .build();
+        const builtServerRequests = spec.buildRequests(bidRequests, {});
+
+        expect(builtServerRequests).to.deep.equal([serverRequest]);
+      });
+    });
   });
 
   describe('interpretResponse', function() {