diff --git a/src/clojure/monger/collection.clj b/src/clojure/monger/collection.clj
index 33aebd4..05f7366 100644
--- a/src/clojure/monger/collection.clj
+++ b/src/clojure/monger/collection.clj
@@ -284,6 +284,21 @@
               false
               write-concern)))
 
+(defn ^WriteResult update-by-ids
+  "Update documents by given ids"
+  ([^DB db ^String coll ids ^Map document]
+     (update-by-ids db coll ids document {}))
+  ([^DB db ^String coll ids ^Map document {:keys [upsert write-concern]
+                                           :or {upsert false
+                                                write-concern mc/*mongodb-write-concern*}}]
+     (check-not-nil! (seq ids) "ids must not be nil or empty")
+     (.update (.getCollection db (name coll))
+              (to-db-object {:_id {"$in" ids}})
+              (to-db-object document)
+              upsert
+              true
+              write-concern)))
+
 
 ;; monger.collection/save
 
diff --git a/test/monger/test/collection_test.clj b/test/monger/test/collection_test.clj
index eb41e3a..ad79fda 100644
--- a/test/monger/test/collection_test.clj
+++ b/test/monger/test/collection_test.clj
@@ -137,6 +137,41 @@
       (is (= ["CA" "IL" "NY"] (sort (mc/distinct db collection :state {}))))
       (is (= ["CA" "NY"] (sort (mc/distinct db collection :state {:price {$gt 100.00}}))))))
 
+  ;;
+  ;; update
+  ;;
+
+  (let [coll "things"
+        batch [{:_id 1 :type "rock" :size "small"}
+               {:_id 2 :type "bed" :size "bed-sized"}
+               {:_id 3 :type "bottle" :size "1.5 liters"}]]
+
+    (deftest test-update
+      (mc/insert-batch db coll batch)
+      (is (= "small" (:size (mc/find-one-as-map db coll {:type "rock"}))))
+      (mc/update db coll {:type "rock"} {"$set" {:size "huge"}})
+      (is (= "huge" (:size (mc/find-one-as-map db coll {:type "rock"})))))
+
+    (deftest test-upsert
+      (is (mc/empty? db coll))
+      (mc/upsert db coll {:_id 4} {"$set" {:size "tiny"}})
+      (is (not (mc/empty? db coll)))
+      (mc/upsert db coll {:_id 4} {"$set" {:size "big"}})
+      (is (= [{:_id 4 :size "big"}] (mc/find-maps db coll {:_id 4}))))
+
+    (deftest test-update-by-id
+      (mc/insert-batch db coll batch)
+      (is (= "bed" (:type (mc/find-one-as-map db coll {:_id 2}))))
+      (mc/update-by-id db coll 2 {"$set" {:type "living room"}})
+      (is (= "living room" (:type (mc/find-one-as-map db coll {:_id 2})))))
+
+    (deftest test-update-by-ids
+      (mc/insert-batch db coll batch)
+      (is (= "bed" (:type (mc/find-one-as-map db coll {:_id 2}))))
+      (is (= "bottle" (:type (mc/find-one-as-map db coll {:_id 3}))))
+      (mc/update-by-ids db coll [2 3] {"$set" {:type "dog"}})
+      (is (= "dog" (:type (mc/find-one-as-map db coll {:_id 2}))))
+      (is (= "dog" (:type (mc/find-one-as-map db coll {:_id 3}))))))
 
   ;;
   ;; miscellenous