diff --git a/sdk/cosmosdb/cosmos/CHANGELOG.md b/sdk/cosmosdb/cosmos/CHANGELOG.md
index 6a31f4605946..008d521794fb 100644
--- a/sdk/cosmosdb/cosmos/CHANGELOG.md
+++ b/sdk/cosmosdb/cosmos/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## 3.9.3 (Unreleased)
 
+- BUGFIX: Fixes bulk operations with top level partitionKey values that are undefined or null.
 
 ## 3.9.2 (2020-09-16)
 
diff --git a/sdk/cosmosdb/cosmos/src/utils/batch.ts b/sdk/cosmosdb/cosmos/src/utils/batch.ts
index 15274fa93725..122cbd50c179 100644
--- a/sdk/cosmosdb/cosmos/src/utils/batch.ts
+++ b/sdk/cosmosdb/cosmos/src/utils/batch.ts
@@ -129,12 +129,19 @@ export function hasResource(
 export function getPartitionKeyToHash(operation: Operation, partitionProperty: string) {
   const toHashKey = hasResource(operation)
     ? (operation.resourceBody as any)[partitionProperty]
-    : operation.partitionKey.replace(/[\[\]\"\']/g, "");
+    : (operation.partitionKey && operation.partitionKey.replace(/[[\]"']/g, "")) ||
+      operation.partitionKey;
   // We check for empty object since replace will stringify the value
   // The second check avoids cases where the partitionKey value is actually the string '{}'
   if (toHashKey === "{}" && operation.partitionKey === "[{}]") {
     return {};
   }
+  if (toHashKey === "null" && operation.partitionKey === "[null]") {
+    return null;
+  }
+  if (toHashKey === "0" && operation.partitionKey === "[0]") {
+    return 0;
+  }
   return toHashKey;
 }
 
@@ -151,7 +158,7 @@ export function decorateOperation(
       operation.resourceBody.id = uuid();
     }
   }
-  if (operation.partitionKey) {
+  if ("partitionKey" in operation) {
     const extracted = extractPartitionKey(operation, { paths: ["/partitionKey"] });
     return { ...operation, partitionKey: JSON.stringify(extracted) } as Operation;
   } else if (
diff --git a/sdk/cosmosdb/cosmos/test/functional/item.spec.ts b/sdk/cosmosdb/cosmos/test/functional/item.spec.ts
index 0d31df9373ed..e945b83bca71 100644
--- a/sdk/cosmosdb/cosmos/test/functional/item.spec.ts
+++ b/sdk/cosmosdb/cosmos/test/functional/item.spec.ts
@@ -441,6 +441,45 @@ describe("bulk item operations", function() {
       const response = await v2Container.items.bulk(operations);
       assert.equal(response[0].statusCode, 201);
     });
+    it("handles operations with null, undefined, and 0 partition keys", async function() {
+      const item1Id = addEntropy("item1");
+      const item2Id = addEntropy("item2");
+      const item3Id = addEntropy("item2");
+      await v2Container.items.create({
+        id: item1Id,
+        key: null,
+        class: "2010"
+      });
+      await v2Container.items.create({
+        id: item2Id,
+        key: 0
+      });
+      await v2Container.items.create({
+        id: item3Id,
+        key: undefined
+      });
+      const operations: OperationInput[] = [
+        {
+          operationType: BulkOperationType.Read,
+          id: item1Id,
+          partitionKey: null
+        },
+        {
+          operationType: BulkOperationType.Read,
+          id: item2Id,
+          partitionKey: 0
+        },
+        {
+          operationType: BulkOperationType.Read,
+          id: item3Id,
+          partitionKey: undefined
+        }
+      ];
+      const response = await v2Container.items.bulk(operations);
+      assert.equal(response[0].statusCode, 200);
+      assert.equal(response[1].statusCode, 200);
+      assert.equal(response[2].statusCode, 200);
+    });
   });
   describe("v2 single partition container", async function() {
     let container: Container;