diff --git a/modules/audienceNetworkBidAdapter.js b/modules/audienceNetworkBidAdapter.js
index 263edba878a..612357e0e4a 100644
--- a/modules/audienceNetworkBidAdapter.js
+++ b/modules/audienceNetworkBidAdapter.js
@@ -27,7 +27,7 @@ const isBidRequestValid = bid =>
   typeof bid.params.placementId === 'string' &&
   bid.params.placementId.length > 0 &&
   Array.isArray(bid.sizes) && bid.sizes.length > 0 &&
-  (isFullWidth(bid.params.format) ? bid.sizes.map(flattenSize).every(size => size === '300x250') : true) &&
+  (isFullWidth(bid.params.format) ? bid.sizes.map(flattenSize).some(size => size === '300x250') : true) &&
   (isValidNonSizedFormat(bid.params.format) || bid.sizes.map(flattenSize).some(isValidSize));
 
 /**
diff --git a/test/spec/modules/audienceNetworkBidAdapter_spec.js b/test/spec/modules/audienceNetworkBidAdapter_spec.js
index 41a6d955c6a..f9d46e100b1 100644
--- a/test/spec/modules/audienceNetworkBidAdapter_spec.js
+++ b/test/spec/modules/audienceNetworkBidAdapter_spec.js
@@ -75,7 +75,7 @@ describe('AudienceNetwork adapter', () => {
     it('fullwidth', () => {
       expect(isBidRequestValid({
         bidder,
-        sizes: [[300, 250]],
+        sizes: [[300, 250], [336, 280]],
         params: {
           placementId,
           format: 'fullwidth'