diff --git a/spec/operators/cache-spec.ts b/spec/operators/cache-spec.ts
deleted file mode 100644
index 828c30a5d70..00000000000
--- a/spec/operators/cache-spec.ts
+++ /dev/null
@@ -1,222 +0,0 @@
-import * as Rx from '../../dist/cjs/Rx';
-import {expect} from 'chai';
-declare const {hot, cold, time, expectObservable, expectSubscriptions};
-
-declare const rxTestScheduler: Rx.TestScheduler;
-
-/** @test {cache} */
-describe('Observable.prototype.cache', () => {
-  it('should just work™', () => {
-    let subs = 0;
-    const source = Rx.Observable.create(observer => {
-      subs++;
-      observer.next(1);
-      observer.next(2);
-      observer.next(3);
-      observer.complete();
-    }).cache();
-    let results = [];
-    source.subscribe(x => results.push(x));
-    expect(results).to.deep.equal([1, 2, 3]);
-    expect(subs).to.equal(1);
-    results = [];
-    source.subscribe(x => results.push(x));
-    expect(results).to.deep.equal([1, 2, 3]);
-    expect(subs).to.equal(1);
-  });
-
-  it('should replay values upon subscription', () => {
-    const s1 = hot(   '----a---b---c---|       ').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '----a---b---c---|       ';
-    const expected2 = '                  (abc|)';
-    const sub2 =      '------------------|     ';
-
-    expectObservable(s1).toBe(expected1);
-    rxTestScheduler.schedule(() => expectObservable(s1).toBe(expected2), time(sub2));
-  });
-
-  it('should not replay values after error with a hot observable', () => {
-    const s1 = hot('---^---a---b---c---#  ').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '----a---b---c---#  ';
-    const expected2 = '                  -';
-    const t = time(   '------------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should be resubscribable after error with a cold observable', () => {
-    const s1 = cold(  '----a---b---c---#                  ').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '----a---b---c---#                  ';
-    const expected2 = '                  ----a---b---c---#';
-    const t = time(   '------------------|                ');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should replay values and and share', () => {
-    const s1 = hot('---^---a---b---c------------d--e--f-|').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '----a---b---c------------d--e--f-|';
-    const expected2 = '                (abc)----d--e--f-|';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should have a bufferCount that limits the replay test 1', () => {
-    const s1 = hot('---^---a---b---c------------d--e--f-|').cache(1);
-    const expected1 = '----a---b---c------------d--e--f-|';
-    const expected2 = '                c--------d--e--f-|';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should have a bufferCount that limits the replay test 2', () => {
-    const s1 = hot(   '----a---b---c------------d--e--f-|').cache(2);
-    const expected1 = '----a---b---c------------d--e--f-|';
-    const expected2 = '                (bc)-----d--e--f-|';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-    rxTestScheduler.schedule(() => expectObservable(s1).toBe(expected2), t);
-  });
-
-  it('should accept a windowTime that limits the replay', () => {
-    const w = time(         '----------|');
-    const s1 = hot('---^---a---b---c------------d--e--f-|').cache(Number.POSITIVE_INFINITY, w, rxTestScheduler);
-    const expected1 = '----a---b---c------------d--e--f-|';
-    const expected2 = '                (bc)-----d--e--f-|';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should handle empty', () => {
-    const s1 =   cold('|').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '|';
-    const expected2 = '                |';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should handle throw', () => {
-    const s1 =   cold('#').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '#';
-    const expected2 = '                #';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should handle never', () => {
-    const s1 =   cold('-').cache(undefined, undefined, rxTestScheduler);
-    const expected1 = '-';
-    const expected2 = '                -';
-    const t = time(   '----------------|');
-
-    expectObservable(s1).toBe(expected1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(expected2);
-    }, t);
-  });
-
-  it('should multicast a completion', () => {
-    const s1 = hot('--a--^--b------c-----d------e-|').cache(undefined, undefined, rxTestScheduler);
-    const t1 = time(    '|                         ');
-    const e1 =          '---b------c-----d------e-|';
-    const t2 = time(    '----------|               ');
-    const e2 =          '          (bc)--d------e-|';
-    const t3 = time(    '----------------|         ');
-    const e3 =          '                (bcd)--e-|';
-
-    const expected = [e1, e2, e3];
-
-    [t1, t2, t3].forEach((t: any, i: number) => {
-      rxTestScheduler.schedule(() => {
-        expectObservable(s1).toBe(expected[i]);
-      }, t);
-    });
-  });
-
-  it('should multicast an error', () => {
-    const s1 = hot('--a--^--b------c-----d------e-#').cache(undefined, undefined, rxTestScheduler);
-    const t1 = time(    '|                         ');
-    const e1 =          '---b------c-----d------e-#';
-    const t2 = time(    '----------|               ');
-    const e2 =          '          (bc)--d------e-#';
-    const t3 = time(    '----------------|         ');
-    const e3 =          '                (bcd)--e-#';
-
-    const expected = [e1, e2, e3];
-
-    [t1, t2, t3].forEach((t: any, i: number) => {
-      rxTestScheduler.schedule(() => {
-        expectObservable(s1).toBe(expected[i]);
-      }, t);
-    });
-  });
-
-  it('should limit replay by both count and a window time, test 2', () => {
-    const w = time(     '-----------|');
-    const s1 = hot('--a--^---b---c----d----e------f--g--h--i-------|').cache(4, w, rxTestScheduler);
-    const e1 =          '----b---c----d----e------f--g--h--i-------|';
-    const t1 = time(    '--------------------|');
-    //                          -----------|
-    const e2 =          '                    (de)-f--g--h--i-------|'; // time wins
-    const t2 = time(    '-----------------------------------|');
-    const e3 =          '                                   (fghi)-|'; // count wins
-    //                                         -----------|
-
-    expectObservable(s1).toBe(e1);
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(e2);
-    }, t1);
-
-    rxTestScheduler.schedule(() => {
-      expectObservable(s1).toBe(e3);
-    }, t2);
-  });
-
-  it('should be retryable', () => {
-    const source = cold('--1-2-3-#');
-    const subs =       ['^       !                ',
-                        '        ^       !        ',
-                        '                ^       !'];
-    const expected =    '--1-2-3---1-2-3---1-2-3-#';
-
-    const result = source.cache(undefined, undefined, rxTestScheduler).retry(2);
-
-    expectObservable(result).toBe(expected);
-    expectSubscriptions(source.subscriptions).toBe(subs);
-  });
-});
\ No newline at end of file
diff --git a/src/Rx.ts b/src/Rx.ts
index 2f4ca8f8bd0..5f52c96d28f 100644
--- a/src/Rx.ts
+++ b/src/Rx.ts
@@ -44,7 +44,6 @@ import './add/operator/bufferCount';
 import './add/operator/bufferTime';
 import './add/operator/bufferToggle';
 import './add/operator/bufferWhen';
-import './add/operator/cache';
 import './add/operator/catch';
 import './add/operator/combineAll';
 import './add/operator/combineLatest';
diff --git a/src/add/operator/cache.ts b/src/add/operator/cache.ts
deleted file mode 100644
index 848112060cf..00000000000
--- a/src/add/operator/cache.ts
+++ /dev/null
@@ -1,11 +0,0 @@
-
-import { Observable } from '../../Observable';
-import { cache, CacheSignature } from '../../operator/cache';
-
-Observable.prototype.cache = cache;
-
-declare module '../../Observable' {
-  interface Observable<T> {
-    cache: CacheSignature<T>;
-  }
-}
\ No newline at end of file
diff --git a/src/operator/cache.ts b/src/operator/cache.ts
deleted file mode 100644
index 7aee840a23e..00000000000
--- a/src/operator/cache.ts
+++ /dev/null
@@ -1,63 +0,0 @@
-import { Observable } from '../Observable';
-import { Scheduler } from '../Scheduler';
-import { ReplaySubject } from '../ReplaySubject';
-import { Observer } from '../Observer';
-import { Subscription } from '../Subscription';
-
-/**
- * @param bufferSize
- * @param windowTime
- * @param scheduler
- * @return {Observable<any>}
- * @method cache
- * @owner Observable
- */
-export function cache<T>(bufferSize: number = Number.POSITIVE_INFINITY,
-                         windowTime: number = Number.POSITIVE_INFINITY,
-                         scheduler?: Scheduler): Observable<T> {
-  let subject: ReplaySubject<T>;
-  let source = this;
-  let refs = 0;
-  let outerSub: Subscription;
-
-  const getSubject = () => {
-    subject = new ReplaySubject<T>(bufferSize, windowTime, scheduler);
-    return subject;
-  };
-
-  return new Observable<T>((observer: Observer<T>) => {
-    if (!subject) {
-      subject = getSubject();
-      outerSub = source.subscribe(
-        (value: T) => subject.next(value),
-        (err: any) => {
-          let s = subject;
-          subject = null;
-          s.error(err);
-        },
-        () => subject.complete()
-      );
-    }
-
-    refs++;
-
-    if (!subject) {
-      subject = getSubject();
-    }
-    let innerSub = subject.subscribe(observer);
-
-    return () => {
-      refs--;
-      if (innerSub) {
-        innerSub.unsubscribe();
-      }
-      if (refs === 0) {
-        outerSub.unsubscribe();
-      }
-    };
-  });
-}
-
-export interface CacheSignature<T> {
-  (bufferSize?: number, windowTime?: number, scheduler?: Scheduler): Observable<T>;
-}