diff --git a/modules/synacormediaBidAdapter.js b/modules/synacormediaBidAdapter.js
index 2ca2aeeae82..8f069f551ee 100644
--- a/modules/synacormediaBidAdapter.js
+++ b/modules/synacormediaBidAdapter.js
@@ -71,38 +71,18 @@ export const spec = {
         pos = 0;
       }
       const videoOrBannerKey = this.isVideoBid(bid) ? 'video' : 'banner';
-      getAdUnitSizes(bid)
-        .filter(size => BLOCKED_AD_SIZES.indexOf(size.join('x')) === -1)
-        .forEach((size, i) => {
-          if (!size || size.length != 2) {
-            return;
-          }
-          const size0 = size[0];
-          const size1 = size[1];
-          const imp = {
-            id: `${videoOrBannerKey.substring(0, 1)}${bid.bidId}-${size0}x${size1}`,
-            tagid: placementId
-          };
-          if (bidFloor !== null && !isNaN(bidFloor)) {
-            imp.bidfloor = bidFloor;
-          }
+      const adSizes = getAdUnitSizes(bid)
+        .filter(size => BLOCKED_AD_SIZES.indexOf(size.join('x')) === -1);
 
-          const videoOrBannerValue = {
-            w: size0,
-            h: size1,
-            pos
-          };
-          if (videoOrBannerKey === 'video') {
-            if (bid.mediaTypes.video) {
-              this.setValidVideoParams(bid.mediaTypes.video, bid.params.video);
-            }
-            if (bid.params.video) {
-              this.setValidVideoParams(bid.params.video, videoOrBannerValue);
-            }
-          }
-          imp[videoOrBannerKey] = videoOrBannerValue;
-          openRtbBidRequest.imp.push(imp);
-        });
+      let imps = [];
+      if (videoOrBannerKey === 'banner') {
+        imps = this.buildBannerImpressions(adSizes, bid, placementId, pos, bidFloor, videoOrBannerKey);
+      } else if (videoOrBannerKey === 'video') {
+        imps = this.buildVideoImpressions(adSizes, bid, placementId, pos, bidFloor, videoOrBannerKey);
+      }
+      if (imps.length > 0) {
+        imps.forEach(i => openRtbBidRequest.imp.push(i));
+      }
     });
 
     if (openRtbBidRequest.imp.length && seatId) {
@@ -118,6 +98,70 @@ export const spec = {
     }
   },
 
+  buildBannerImpressions: function(adSizes, bid, placementId, pos, bidFloor, videoOrBannerKey) {
+    let format = [];
+    let imps = [];
+    adSizes.forEach((size, i) => {
+      if (!size || size.length !== 2) {
+        return;
+      }
+
+      format.push({
+        w: size[0],
+        h: size[1],
+      });
+    });
+
+    if (format.length > 0) {
+      const imp = {
+        id: `${videoOrBannerKey.substring(0, 1)}${bid.bidId}`,
+        banner: {
+          format,
+          pos
+        },
+        tagid: placementId,
+      };
+      if (bidFloor !== null && !isNaN(bidFloor)) {
+        imp.bidfloor = bidFloor;
+      }
+      imps.push(imp);
+    }
+    return imps;
+  },
+
+  buildVideoImpressions: function(adSizes, bid, placementId, pos, bidFloor, videoOrBannerKey) {
+    let imps = [];
+    adSizes.forEach((size, i) => {
+      if (!size || size.length != 2) {
+        return;
+      }
+      const size0 = size[0];
+      const size1 = size[1];
+      const imp = {
+        id: `${videoOrBannerKey.substring(0, 1)}${bid.bidId}-${size0}x${size1}`,
+        tagid: placementId
+      };
+      if (bidFloor !== null && !isNaN(bidFloor)) {
+        imp.bidfloor = bidFloor;
+      }
+
+      const videoOrBannerValue = {
+        w: size0,
+        h: size1,
+        pos
+      };
+      if (bid.mediaTypes.video) {
+        this.setValidVideoParams(bid.mediaTypes.video, bid.params.video);
+      }
+      if (bid.params.video) {
+        this.setValidVideoParams(bid.params.video, videoOrBannerValue);
+      }
+      imp[videoOrBannerKey] = videoOrBannerValue;
+      imps.push(imp);
+    });
+    return imps;
+  },
+
   setValidVideoParams: function (sourceObj, destObj) {
     Object.keys(sourceObj)
       .filter(param => includes(VIDEO_PARAMS, param) && sourceObj[param] !== null && (!isNaN(parseInt(sourceObj[param], 10)) || !(sourceObj[param].length < 1)))
diff --git a/modules/synacormediaBidAdapter.md b/modules/synacormediaBidAdapter.md
index 857cf15d240..fd71f07b3a3 100644
--- a/modules/synacormediaBidAdapter.md
+++ b/modules/synacormediaBidAdapter.md
@@ -42,8 +42,10 @@ https://track.technoratimedia.com/openrtb/tags?ID=%%PATTERN:hb_cache_id_synacorm
       code: 'test-div2',
       mediaTypes: {
         video: {
-            context: 'instream',
-            playerSize: [[300, 250]],
+          context: 'instream',
+          playerSize: [
+            [300, 250]
+          ],
         }
       },
       bids: [{
diff --git a/test/spec/modules/synacormediaBidAdapter_spec.js b/test/spec/modules/synacormediaBidAdapter_spec.js
index f6fa7a20594..e15481d47e5 100644
--- a/test/spec/modules/synacormediaBidAdapter_spec.js
+++ b/test/spec/modules/synacormediaBidAdapter_spec.js
@@ -68,9 +68,13 @@ describe('synacormediaBidAdapter ', function () {
       },
       mediaTypes: {
         banner: {
-          h: 600,
-          pos: 0,
-          w: 300,
+          format: [
+            {
+              w: 300,
+              h: 600
+            }
+          ],
+          pos: 0
         }
       },
     };
@@ -173,21 +177,19 @@ describe('synacormediaBidAdapter ', function () {
 
     let expectedDataImp1 = {
       banner: {
-        h: 250,
-        pos: 0,
-        w: 300,
-      },
-      id: 'b9876abcd-300x250',
-      tagid: '1234',
-      bidfloor: 0.5
-    };
-    let expectedDataImp2 = {
-      banner: {
-        h: 600,
-        pos: 0,
-        w: 300,
+        format: [
+          {
+            h: 250,
+            w: 300
+          },
+          {
+            h: 600,
+            w: 300
+          }
+        ],
+        pos: 0
       },
-      id: 'b9876abcd-300x600',
+      id: 'b9876abcd',
       tagid: '1234',
       bidfloor: 0.5
     };
@@ -201,7 +203,7 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.url).to.contain('https://prebid.technoratimedia.com/openrtb/bids/prebid?');
       expect(req.data).to.exist.and.to.be.an('object');
       expect(req.data.id).to.equal('xyz123');
-      expect(req.data.imp).to.eql([expectedDataImp1, expectedDataImp2]);
+      expect(req.data.imp).to.eql([expectedDataImp1]);
 
       // video test
       let reqVideo = spec.buildRequests([validBidRequestVideo], bidderRequestVideo);
@@ -230,13 +232,17 @@ describe('synacormediaBidAdapter ', function () {
       expect(req).to.have.property('url');
       expect(req.url).to.contain('https://prebid.technoratimedia.com/openrtb/bids/prebid?');
       expect(req.data.id).to.equal('xyz123');
-      expect(req.data.imp).to.eql([expectedDataImp1, expectedDataImp2, {
+      expect(req.data.imp).to.eql([expectedDataImp1, {
         banner: {
-          h: 600,
-          pos: 0,
-          w: 300,
+          format: [
+            {
+              h: 600,
+              w: 300
+            }
+          ],
+          pos: 0
         },
-        id: 'bfoobar-300x600',
+        id: 'bfoobar',
         tagid: '5678',
         bidfloor: 0.5
       }]);
@@ -260,11 +266,15 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.data.imp).to.eql([
         {
           banner: {
-            h: 250,
-            pos: 0,
-            w: 300,
+            format: [
+              {
+                h: 250,
+                w: 300
+              }
+            ],
+            pos: 0
           },
-          id: 'bfoobar-300x250',
+          id: 'bfoobar',
           tagid: '5678',
           bidfloor: 0.5
         }
@@ -289,11 +299,15 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.data.imp).to.eql([
         {
           banner: {
-            h: 250,
-            pos: 0,
-            w: 300,
+            format: [
+              {
+                h: 250,
+                w: 300
+              }
+            ],
+            pos: 0
           },
-          id: 'b9876abcd-300x250',
+          id: 'b9876abcd',
           tagid: '1234',
         }
       ]);
@@ -316,11 +330,15 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.data.imp).to.eql([
         {
           banner: {
-            h: 250,
-            pos: 0,
-            w: 300,
+            format: [
+              {
+                h: 250,
+                w: 300
+              }
+            ],
+            pos: 0
           },
-          id: 'b9876abcd-300x250',
+          id: 'b9876abcd',
           tagid: '1234',
         }
       ]);
@@ -344,11 +362,15 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.data.imp).to.eql([
         {
           banner: {
-            h: 250,
-            w: 300,
-            pos: 1,
+            format: [
+              {
+                h: 250,
+                w: 300
+              }
+            ],
+            pos: 1
           },
-          id: 'b9876abcd-300x250',
+          id: 'b9876abcd',
           tagid: '1234'
         }
       ]);
@@ -371,11 +393,15 @@ describe('synacormediaBidAdapter ', function () {
       expect(req.data.imp).to.eql([
         {
           banner: {
-            h: 250,
-            w: 300,
-            pos: 0,
+            format: [
+              {
+                h: 250,
+                w: 300
+              }
+            ],
+            pos: 0
           },
-          id: 'b9876abcd-300x250',
+          id: 'b9876abcd',
           tagid: '1234'
         }
       ]);