diff --git a/types/redux-immutable/index.d.ts b/types/redux-immutable/index.d.ts
index 483de7c9bf..ebebd7a84c 100644
--- a/types/redux-immutable/index.d.ts
+++ b/types/redux-immutable/index.d.ts
@@ -1,8 +1,12 @@
-// Type definitions for redux-immutable v3.0.10
+// Type definitions for redux-immutable v3.0.33
 // Project: https://github.com/gajus/redux-immutable
-// Definitions by: Pedro Pereira <https://github.com/oizie>, Sebastian Sebald <https://github.com/sebald/>
+// Definitions by: Pedro Pereira <https://github.com/oizie>
+//                 Sebastian Sebald <https://github.com/sebald/>
+//                 Gavin Gregory <https://github.com/gavingregory>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
 import * as Redux from 'redux';
+import { Collection } from 'immutable';
 
-export declare function combineReducers<S>(reducers: Redux.ReducersMapObject): Redux.Reducer<S>;
+export declare function combineReducers<S, T>(reducers: Redux.ReducersMapObject, getDefaultState?: () => Collection.Keyed<T, S>): Redux.Reducer<S>;
+export declare function combineReducers<S>(reducers: Redux.ReducersMapObject, getDefaultState?: () => Collection.Indexed<S>): Redux.Reducer<S>;
diff --git a/types/redux-immutable/package.json b/types/redux-immutable/package.json
index e52256ea90..be19181dda 100644
--- a/types/redux-immutable/package.json
+++ b/types/redux-immutable/package.json
@@ -1,5 +1,6 @@
 {
   "dependencies": {
-    "redux": "^3.6.0"
+    "redux": "^3.6.0",
+    "immutable": "^3.8.1"
   }
 }
\ No newline at end of file
diff --git a/types/redux-immutable/redux-immutable-tests.ts b/types/redux-immutable/redux-immutable-tests.ts
index 8414252299..c790ce545e 100644
--- a/types/redux-immutable/redux-immutable-tests.ts
+++ b/types/redux-immutable/redux-immutable-tests.ts
@@ -1,5 +1,22 @@
 
 import { combineReducers } from 'redux-immutable';
+import { Map, List } from 'immutable';
 
-combineReducers({
-});
\ No newline at end of file
+// Dummy State interface
+interface State { };
+
+/**
+ * Combine reducers should work with only one argument (a reducers object).
+ */
+combineReducers({});
+combineReducers<State>({});
+
+/**
+ * Combine reducers should accepts a function (getDefaultState()) as a second parameter, that returns an immutable Collection.Keyed collection.
+ */
+combineReducers<State, string>({}, () => { return Map<string, State>(); });
+combineReducers<State, number>({}, () => { return Map<number, State>(); });
+/**
+ * Combine reducers should accepts a function (getDefaultState()) as a second parameter, that returns an immutable Collection.Indexed collection.
+ */
+combineReducers<State>({}, () => { return List<State>(); });