diff --git a/src/CoreOperators.ts b/src/CoreOperators.ts
index cc47bdefe5..bd24d5c175 100644
--- a/src/CoreOperators.ts
+++ b/src/CoreOperators.ts
@@ -28,7 +28,7 @@ export interface CoreOperators<T> {
   do?: (next?: (x: T) => void, error?: (e: any) => void, complete?: () => void) => Observable<T>;
   expand?: <R>(project: (x: T, ix: number) => Observable<R>, concurrent: number, scheduler: Scheduler) => Observable<R>;
   filter?: (predicate: (x: T) => boolean, ix?: number, thisArg?: any) => Observable<T>;
-  finally?: (ensure: () => void, thisArg?: any) => Observable<T>;
+  finally?: (finallySelector: () => void) => Observable<T>;
   first?: <R>(predicate?: (value: T, index: number, source: Observable<T>) => boolean,
               resultSelector?: (value: T, index: number) => R, thisArg?: any, defaultValue?: any) => Observable<T> | Observable<R>;
   flatMap?: <R>(project: ((x: T, ix: number) => Observable<any>),
diff --git a/src/Observable.ts b/src/Observable.ts
index 88a5175604..bb065d6307 100644
--- a/src/Observable.ts
+++ b/src/Observable.ts
@@ -190,7 +190,7 @@ export class Observable<T> implements CoreOperators<T>  {
   do: (next?: (x: T) => void, error?: (e: any) => void, complete?: () => void) => Observable<T>;
   expand: <R>(project: (x: T, ix: number) => Observable<R>, concurrent: number, scheduler: Scheduler) => Observable<R>;
   filter: (predicate: (x: T) => boolean, ix?: number, thisArg?: any) => Observable<T>;
-  finally: (ensure: () => void, thisArg?: any) => Observable<T>;
+  finally: (finallySelector: () => void) => Observable<T>;
   first: <R>(predicate?: (value: T, index: number, source: Observable<T>) => boolean,
              resultSelector?: (value: T, index: number) => R, thisArg?: any, defaultValue?: any) => Observable<T> | Observable<R>;
   flatMap: <R>(project: ((x: T, ix: number) => Observable<any>),
diff --git a/src/operator/finally.ts b/src/operator/finally.ts
index f4168f1209..766ed6e650 100644
--- a/src/operator/finally.ts
+++ b/src/operator/finally.ts
@@ -1,20 +1,13 @@
 import {Operator} from '../Operator';
 import {Subscriber} from '../Subscriber';
 import {Subscription} from '../Subscription';
-import {bindCallback} from '../util/bindCallback';
 
-export function _finally<T>(finallySelector: () => void, thisArg?: any) {
-  return this.lift(new FinallyOperator(thisArg ?
-    <() => void> bindCallback(finallySelector, thisArg, 2) :
-    finallySelector));
+export function _finally<T>(finallySelector: () => void) {
+  return this.lift(new FinallyOperator(finallySelector));
 }
 
 class FinallyOperator<T, R> implements Operator<T, R> {
-
-  finallySelector: () => void;
-
-  constructor(finallySelector: () => void) {
-    this.finallySelector = finallySelector;
+  constructor(private finallySelector: () => void) {
   }
 
   call(subscriber: Subscriber<T>): Subscriber<T> {
@@ -27,4 +20,4 @@ class FinallySubscriber<T> extends Subscriber<T> {
     super(destination);
     this.add(new Subscription(finallySelector));
   }
-}
+}
\ No newline at end of file