diff --git a/src/Paket.Core/RemoteDownload.fs b/src/Paket.Core/RemoteDownload.fs
index 6f8ca623e1..899d60d8c1 100644
--- a/src/Paket.Core/RemoteDownload.fs
+++ b/src/Paket.Core/RemoteDownload.fs
@@ -11,17 +11,11 @@ open Paket.Domain
 open Paket.Git.CommandHelper
 open Paket.Git.Handling
 
-let private githubCache = System.Collections.Concurrent.ConcurrentDictionary<_, _>()
 
-let private lookupDocument (auth,url : string)  = async {
-    let key = auth,url
-    match githubCache.TryGetValue key with
-    | true, document -> return document
-    | _ ->
-        let! document = safeGetFromUrl(auth, url, null)
-        githubCache.TryAdd(key, document) |> ignore
-        return document
-    }
+let private safeGetFromUrlCached = memoizeAsync <| safeGetFromUrl
+
+let private lookupDocument (auth,url : string)  = 
+    safeGetFromUrlCached(auth,url,null)
 
 let private auth key url = 
     key
diff --git a/src/Paket.Core/Utils.fs b/src/Paket.Core/Utils.fs
index 1f0ec14d12..baa245d0ae 100644
--- a/src/Paket.Core/Utils.fs
+++ b/src/Paket.Core/Utils.fs
@@ -28,6 +28,11 @@ let internal memoize (f: 'a -> 'b) : 'a -> 'b =
     fun (x: 'a) ->
         cache.GetOrAdd(x, f)
 
+let internal memoizeAsync f =
+    let cache = System.Collections.Concurrent.ConcurrentDictionary<'a, System.Threading.Tasks.Task<'b>>()
+    fun (x: 'a) -> // task.Result serialization to sync after done.
+        cache.GetOrAdd(x, fun x -> f(x) |> Async.StartAsTask) |> Async.AwaitTask
+
 type Auth = 
     | Credentials of Username : string * Password : string
     | Token of string
diff --git a/tests/Paket.Tests/DependenciesFile/ParserSpecs.fs b/tests/Paket.Tests/DependenciesFile/ParserSpecs.fs
index 8de8f7c516..3ac7351f3e 100644
--- a/tests/Paket.Tests/DependenciesFile/ParserSpecs.fs
+++ b/tests/Paket.Tests/DependenciesFile/ParserSpecs.fs
@@ -1343,4 +1343,34 @@ let ``should read config with caches``() =
 
     (main.Sources |> List.item 0) |> shouldEqual PackageSources.DefaultNuGetSource
     (main.Sources |> List.item 1).Url |> shouldEqual "./dependencies"
-    (main.Sources |> List.item 2).Url |> shouldEqual "//hive/dependencies"
\ No newline at end of file
+    (main.Sources |> List.item 2).Url |> shouldEqual "//hive/dependencies"
+
+[<Test>]
+let ``async cache should work``() =
+    let mutable x = 0
+    let someSlowFunc mykey = async { 
+        Console.WriteLine "Simulated downloading..."
+        do! Async.Sleep 400
+        Console.WriteLine "Simulated downloading Done."
+        x <- x + 1 // Side effect!
+        return "" }
+    let memFunc = memoizeAsync <| someSlowFunc
+    async {
+        do! memFunc "a" |> Async.Ignore
+        do! memFunc "a" |> Async.Ignore
+        do! memFunc "a" |> Async.Ignore
+        do! [|1 .. 30|] |> Seq.map(fun _ -> (memFunc "a")) 
+            |> Async.Parallel |> Async.Ignore
+        for i = 1 to 30 do
+            Async.Start( memFunc "a" |> Async.Ignore )
+            Async.Start( memFunc "a" |> Async.Ignore )
+        do! Async.Sleep 500
+        do! memFunc "a" |> Async.Ignore
+        do! memFunc "a" |> Async.Ignore
+        for i = 1 to 30 do
+            Async.Start( memFunc "a" |> Async.Ignore )
+        do! [|1 .. 30|] |> Seq.map(fun _ -> (memFunc "a")) 
+            |> Async.Parallel |> Async.Ignore
+    } |> Async.RunSynchronously
+    x |> shouldEqual 1
+