diff --git a/modules/rtbhouseBidAdapter.js b/modules/rtbhouseBidAdapter.js
index 245fc5f3ea2..36c08fc8626 100644
--- a/modules/rtbhouseBidAdapter.js
+++ b/modules/rtbhouseBidAdapter.js
@@ -115,10 +115,11 @@ function mapBanner(slot) {
   if (slot.mediaType === 'banner' ||
     utils.deepAccess(slot, 'mediaTypes.banner') ||
     (!slot.mediaType && !slot.mediaTypes)) {
+    var sizes = slot.sizes || slot.mediaTypes.banner.sizes;
     return {
-      w: slot.sizes[0][0],
-      h: slot.sizes[0][1],
-      format: slot.sizes.map(size => ({
+      w: sizes[0][0],
+      h: sizes[0][1],
+      format: sizes.map(size => ({
         w: size[0],
         h: size[1]
       }))
diff --git a/modules/rtbhouseBidAdapter.md b/modules/rtbhouseBidAdapter.md
index 233ed34053a..b8b59aa9edc 100644
--- a/modules/rtbhouseBidAdapter.md
+++ b/modules/rtbhouseBidAdapter.md
@@ -17,7 +17,11 @@ Please reach out to pmp@rtbhouse.com to receive your own
            // banner
            {
                code: 'test-div',
-               sizes: [[300, 250]],
+               mediaTypes: {
+	           banner: {
+                       sizes: [[300, 250]],
+                   }
+               },
                bids: [
                    {
                        bidder: "rtbhouse",
diff --git a/test/spec/modules/rtbhouseBidAdapter_spec.js b/test/spec/modules/rtbhouseBidAdapter_spec.js
index 707a5f91bec..67845fa1983 100644
--- a/test/spec/modules/rtbhouseBidAdapter_spec.js
+++ b/test/spec/modules/rtbhouseBidAdapter_spec.js
@@ -19,7 +19,11 @@ describe('RTBHouseAdapter', () => {
         'region': 'prebid-eu'
       },
       'adUnitCode': 'adunit-code',
-      'sizes': [[300, 250], [300, 600]],
+      'mediaTypes': {
+        'banner': {
+          'sizes': [[300, 250], [300, 600]],
+        }
+      },
       'bidId': '30b31c1838de1e',
       'bidderRequestId': '22edbae2733bf6',
       'auctionId': '1d1a030790a475'
@@ -29,6 +33,13 @@ describe('RTBHouseAdapter', () => {
       expect(spec.isBidRequestValid(bid)).to.equal(true);
     });
 
+    it('Checking backward compatibility. should return true', function () {
+      let bid2 = Object.assign({}, bid);
+      delete bid2.mediaTypes;
+      bid2.sizes = [[300, 250], [300, 600]];
+      expect(spec.isBidRequestValid(bid2)).to.equal(true);
+    });
+
     it('should return false when required params are not passed', function () {
       let bid = Object.assign({}, bid);
       delete bid.params;
@@ -49,7 +60,11 @@ describe('RTBHouseAdapter', () => {
           'test': 1
         },
         'adUnitCode': 'adunit-code',
-        'sizes': [[300, 250], [300, 600]],
+        'mediaTypes': {
+          'banner': {
+            'sizes': [[300, 250], [300, 600]],
+          }
+        },
         'bidId': '30b31c1838de1e',
         'bidderRequestId': '22edbae2733bf6',
         'auctionId': '1d1a030790a475',