diff --git a/types/knockout/index.d.ts b/types/knockout/index.d.ts
index 6773ec8c23..fd788fbc72 100644
--- a/types/knockout/index.d.ts
+++ b/types/knockout/index.d.ts
@@ -409,10 +409,6 @@ interface KnockoutTasks {
 }
 
 /////////////////////////////////
-type KnockoutObservableType<T> = {
-    [P in keyof T]: KnockoutObservable<T[P]>;
-};
-
 interface KnockoutStatic {
     utils: KnockoutUtils;
     memoization: KnockoutMemoization;
@@ -443,12 +439,18 @@ interface KnockoutStatic {
     contextFor(node: any): any;
     isSubscribable(instance: any): instance is KnockoutSubscribable<any>;
     toJSON(viewModel: any, replacer?: Function, space?: any): string;
-    toJS<T>(viewModel: KnockoutObservableArray<T>|KnockoutObservableType<T>[]|KnockoutObservableArray<KnockoutObservableType<T>>|T[]): T[];
-    toJS<T>(viewModel: KnockoutObservable<T>|KnockoutObservableType<T>|KnockoutObservable<KnockoutObservableType<T>>): T;
-    toJS<T>(viewModel: T): T;
-    isObservable<T>(instance: KnockoutObservable<T>|T): instance is KnockoutObservable<T>;
-    isWriteableObservable<T>(instance: KnockoutObservable<T>|T): instance is KnockoutObservable<T>;
-    isComputed<T>(instance: KnockoutObservable<T>|T): instance is KnockoutComputed<T>;
+  
+    toJS(viewModel: any): any;
+
+    isObservable(instance: any): instance is KnockoutObservable<any>;
+    isObservable<T>(instance: KnockoutObservable<T>): instance is KnockoutObservable<T>;
+
+    isWriteableObservable(instance: any): instance is KnockoutObservable<any>;
+    isWriteableObservable<T>(instance: KnockoutObservable<T>): instance is KnockoutObservable<T>;
+
+    isComputed(instance: any): instance is KnockoutComputed<any>;
+    isComputed<T>(instance: KnockoutObservable<T> | T): instance is KnockoutComputed<T>;
+  
     dataFor(node: any): any;
     removeNode(node: Node): void;
     cleanNode(node: Node): Node;
diff --git a/types/knockout/test/index.ts b/types/knockout/test/index.ts
index 36db7657ed..bc62702e0d 100644
--- a/types/knockout/test/index.ts
+++ b/types/knockout/test/index.ts
@@ -99,6 +99,19 @@ class GetterViewModel {
     public range: KnockoutObservable<any>;
 }
 
+function testToJs() {
+    var objKo = {
+        prop: ko.observable("prop"),
+        subKo: ko.observable({
+            prop: ko.observable("prop")
+        })
+    };
+
+    var objJs = ko.toJS(objKo);
+    objJs.prop; // $ExpectType any
+    objJs.subKo.prop; // $ExpectType any
+}
+
 function testGetter() {
     var model = new GetterViewModel();