diff --git a/modules/prebidServerBidAdapter/index.js b/modules/prebidServerBidAdapter/index.js
index 4ac1bccaeda..e857bf1d665 100644
--- a/modules/prebidServerBidAdapter/index.js
+++ b/modules/prebidServerBidAdapter/index.js
@@ -495,11 +495,21 @@ const OPEN_RTB_PROTOCOL = {
       const imp = { id: adUnit.code, ext, secure: _s2sConfig.secure };
 
       if (banner) { imp.banner = banner; }
-      if (video) { imp.video = video; }
-
-      imps.push(imp);
+      if (video) {
+        if (video.context === 'outstream' && !adUnit.renderer) {
+          // Don't push oustream w/o renderer to request object.
+          utils.logError('Outstream bid without renderer cannot be sent to Prebid Server.');
+        } else {
+          imp.video = video;
+        }
+      }
+      if (imp.banner || imp.video) { imps.push(imp); }
     });
 
+    if (!imps.length) {
+      utils.logError('Request to Prebid Server rejected due to invalid media type(s) in adUnit.')
+      return;
+    }
     const request = {
       id: s2sBidRequest.tid,
       source: {tid: s2sBidRequest.tid},
@@ -626,6 +636,9 @@ const OPEN_RTB_PROTOCOL = {
 
           if (utils.deepAccess(bid, 'ext.prebid.type') === VIDEO) {
             bidObject.mediaType = VIDEO;
+            let sizes = bidRequest.sizes && bidRequest.sizes[0];
+            bidObject.playerHeight = sizes[0];
+            bidObject.playerWidth = sizes[1];
 
             // try to get cache values from 'response.ext.prebid.cache'
             // else try 'bid.ext.prebid.targeting' as fallback
@@ -721,17 +734,18 @@ export function PrebidServer() {
     }
 
     const request = protocolAdapter().buildRequest(s2sBidRequest, bidRequests, adUnitsWithSizes);
-    const requestJson = JSON.stringify(request);
-
-    ajax(
-      _s2sConfig.endpoint,
-      {
-        success: response => handleResponse(response, requestedBidders, bidRequests, addBidResponse, done),
-        error: done
-      },
-      requestJson,
-      { contentType: 'text/plain', withCredentials: true }
-    );
+    const requestJson = request && JSON.stringify(request);
+    if (request && requestJson) {
+      ajax(
+        _s2sConfig.endpoint,
+        {
+          success: response => handleResponse(response, requestedBidders, bidRequests, addBidResponse, done),
+          error: done
+        },
+        requestJson,
+        { contentType: 'text/plain', withCredentials: true }
+      );
+    }
   };
 
   /* Notify Prebid of bid responses so bids can get in the auction */
diff --git a/test/spec/modules/prebidServerBidAdapter_spec.js b/test/spec/modules/prebidServerBidAdapter_spec.js
index e2a3a5b111a..9562b2f4c07 100644
--- a/test/spec/modules/prebidServerBidAdapter_spec.js
+++ b/test/spec/modules/prebidServerBidAdapter_spec.js
@@ -80,6 +80,69 @@ const VIDEO_REQUEST = {
   ]
 };
 
+const OUTSTREAM_VIDEO_REQUEST = {
+  'account_id': '1',
+  'tid': '437fbbf5-33f5-487a-8e16-a7112903cfe5',
+  'max_bids': 1,
+  'timeout_millis': 1000,
+  'secure': 0,
+  'url': '',
+  'prebid_version': '1.4.0-pre',
+  'ad_units': [
+    {
+      'code': 'div-gpt-ad-1460505748561-0',
+      'sizes': [640, 480],
+      'mediaTypes': {
+        'video': {
+          playerSize: [[ 640, 480 ]],
+          context: 'outstream',
+          mimes: ['video/mp4']
+        },
+        banner: { sizes: [[300, 250]] }
+      },
+      'transactionId': '4ef956ad-fd83-406d-bd35-e4bb786ab86c',
+      'bids': [
+        {
+          'bid_id': '123',
+          'bidder': 'appnexus',
+          'params': { 'placementId': '12349520' }
+        }
+      ]
+    },
+    {
+      code: 'video1',
+      mediaTypes: {
+        video: {
+          playerSize: [640, 480],
+          context: 'outstream',
+          mimes: ['video/mp4']
+        }
+      },
+      bids: [
+        {
+          bidder: 'appnexus',
+          params: {
+            placementId: 13232385,
+            video: {
+              skippable: true,
+              playback_method: ['auto_play_sound_off']
+            }
+          }
+        }
+      ],
+      renderer: {
+        url: 'http://cdn.adnxs.com/renderer/video/ANOutstreamVideo.js',
+        render: function (bid) {
+          ANOutstreamVideo.renderAd({
+            targetId: bid.adUnitCode,
+            adResponse: bid.adResponse,
+          });
+        }
+      }
+    }
+  ]
+};
+
 let BID_REQUESTS;
 
 const RESPONSE = {
@@ -390,6 +453,18 @@ describe('S2S Adapter', function () {
       xhr.restore();
     });
 
+    it('should not add outstrean without renderer', function() {
+      let ortb2Config = utils.deepClone(CONFIG);
+      ortb2Config.endpoint = 'https://prebid.adnxs.com/pbs/v1/openrtb2/auction'
+
+      config.setConfig({s2sConfig: ortb2Config});
+      adapter.callBids(OUTSTREAM_VIDEO_REQUEST, BID_REQUESTS, addBidResponse, done, ajax);
+
+      const requestBid = JSON.parse(requests[0].requestBody);
+      expect(requestBid.imp[0].banner).to.exist;
+      expect(requestBid.imp[0].video).to.not.exist;
+    });
+
     it('exists and is a function', function () {
       expect(adapter.callBids).to.exist.and.to.be.a('function');
     });