diff --git a/spec/operators/find-spec.ts b/spec/operators/find-spec.ts
index 2bc480b196..8b85c503e1 100644
--- a/spec/operators/find-spec.ts
+++ b/spec/operators/find-spec.ts
@@ -1,10 +1,13 @@
 import { expect } from 'chai';
-import { find, mergeMap } from 'rxjs/operators';
+import { find, mergeMap, delay } from 'rxjs/operators';
+import { TestScheduler } from 'rxjs/testing';
 import { hot, cold, expectObservable, expectSubscriptions } from '../helpers/marble-testing';
 import { of, Observable, from } from 'rxjs';
 
 declare function asDiagram(arg: string): Function;
 
+declare const rxTestScheduler: TestScheduler;
+
 /** @test {find} */
 describe('find operator', () => {
   function truePredicate(x: any) {
@@ -19,13 +22,13 @@ describe('find operator', () => {
 
     const predicate = function (x: number) { return x % 5 === 0; };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected, values);
+    expectObservable(source.pipe(find(predicate))).toBe(expected, values);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
   it('should throw if not provided a function', () => {
     expect(() => {
-      (<any>of('yut', 'yee', 'sam')).pipe(find('yee' as any));
+      of('yut', 'yee', 'sam').pipe(find('yee' as any));
     }).to.throw(TypeError, 'predicate is not a function');
   });
 
@@ -34,7 +37,7 @@ describe('find operator', () => {
     const subs =       '^';
     const expected =   '-';
 
-    expectObservable((<any>source).pipe(find(truePredicate))).toBe(expected);
+    expectObservable(source.pipe(find(truePredicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -43,7 +46,7 @@ describe('find operator', () => {
     const subs =        '(^!)';
     const expected =    '(x|)';
 
-    const result = (<any>source).pipe(find(truePredicate));
+    const result = source.pipe(find(truePredicate));
 
     expectObservable(result).toBe(expected, {x: undefined});
     expectSubscriptions(source.subscriptions).toBe(subs);
@@ -58,7 +61,7 @@ describe('find operator', () => {
       return value === 'a';
     };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected);
+    expectObservable(source.pipe(find(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -71,7 +74,7 @@ describe('find operator', () => {
       return value === 'b';
     };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected);
+    expectObservable(source.pipe(find(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -87,7 +90,7 @@ describe('find operator', () => {
       return value === this.target;
     };
 
-    expectObservable((<any>source).pipe(find(predicate, finder))).toBe(expected);
+    expectObservable(source.pipe(find(predicate, finder))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -100,7 +103,7 @@ describe('find operator', () => {
       return value === 'z';
     };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected, { x: undefined });
+    expectObservable(source.pipe(find(predicate))).toBe(expected, { x: undefined });
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -110,7 +113,7 @@ describe('find operator', () => {
     const expected =   '-------     ';
     const unsub =      '      !     ';
 
-    const result = (<any>source).pipe(find((value: string) => value === 'z'));
+    const result = source.pipe(find((value: string) => value === 'z'));
 
     expectObservable(result, unsub).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
@@ -122,7 +125,7 @@ describe('find operator', () => {
     const expected =   '-------     ';
     const unsub =      '      !     ';
 
-    const result = (<any>source).pipe(
+    const result = source.pipe(
       mergeMap((x: string) => of(x)),
       find((value: string) => value === 'z'),
       mergeMap((x: string) => of(x))
@@ -132,6 +135,20 @@ describe('find operator', () => {
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
+  it('should unsubscribe when the predicate is matched', () => {
+    const source = hot('--a--b---c-|');
+    const subs =       '^    !';
+    const expected =   '-------(b|)';
+
+    const duration = rxTestScheduler.createTime('--|');
+
+    expectObservable(source.pipe(
+      find((value: string) => value === 'b'),
+      delay(duration, rxTestScheduler)
+    )).toBe(expected);
+    expectSubscriptions(source.subscriptions).toBe(subs);
+  });
+
   it('should raise if source raise error while element does not match with predicate', () => {
     const source = hot('--a--b--#');
     const subs =       '^       !';
@@ -141,7 +158,7 @@ describe('find operator', () => {
       return value === 'z';
     };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected);
+    expectObservable(source.pipe(find(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -154,7 +171,7 @@ describe('find operator', () => {
       throw 'error';
     };
 
-    expectObservable((<any>source).pipe(find(predicate))).toBe(expected);
+    expectObservable(source.pipe(find(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
diff --git a/spec/operators/findIndex-spec.ts b/spec/operators/findIndex-spec.ts
index 018e402214..1dd023bf4c 100644
--- a/spec/operators/findIndex-spec.ts
+++ b/spec/operators/findIndex-spec.ts
@@ -1,9 +1,12 @@
-import { findIndex, mergeMap } from 'rxjs/operators';
+import { findIndex, mergeMap, delay } from 'rxjs/operators';
+import { TestScheduler } from 'rxjs/testing';
 import { hot, cold, expectObservable, expectSubscriptions } from '../helpers/marble-testing';
 import { of } from 'rxjs';
 
 declare function asDiagram(arg: string): Function;
 
+declare const rxTestScheduler: TestScheduler;
+
 /** @test {findIndex} */
 describe('findIndex operator', () => {
   function truePredicate(x: any) {
@@ -18,7 +21,7 @@ describe('findIndex operator', () => {
 
     const predicate = function (x: number) { return x % 5 === 0; };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected, { x: 2 });
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected, { x: 2 });
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -27,7 +30,7 @@ describe('findIndex operator', () => {
     const subs =       '^';
     const expected =   '-';
 
-    expectObservable((<any>source).pipe(findIndex(truePredicate))).toBe(expected);
+    expectObservable(source.pipe(findIndex(truePredicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -36,7 +39,7 @@ describe('findIndex operator', () => {
     const subs =        '(^!)';
     const expected =    '(x|)';
 
-    const result = (<any>source).pipe(findIndex(truePredicate));
+    const result = source.pipe(findIndex(truePredicate));
 
     expectObservable(result).toBe(expected, {x: -1});
     expectSubscriptions(source.subscriptions).toBe(subs);
@@ -52,7 +55,7 @@ describe('findIndex operator', () => {
       return value === sourceValue;
     };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected, { x: 0 });
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected, { x: 0 });
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -65,7 +68,7 @@ describe('findIndex operator', () => {
       return value === 7;
     };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected, { x: 1 });
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected, { x: 1 });
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -78,7 +81,7 @@ describe('findIndex operator', () => {
     const predicate = function (this: typeof sourceValues, value: number) {
       return value === this.b;
     };
-    const result = (<any>source).pipe(findIndex(predicate, sourceValues));
+    const result = source.pipe(findIndex(predicate, sourceValues));
 
     expectObservable(result).toBe(expected, { x: 1 });
     expectSubscriptions(source.subscriptions).toBe(subs);
@@ -93,7 +96,7 @@ describe('findIndex operator', () => {
       return value === 'z';
     };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected, { x: -1 });
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected, { x: -1 });
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -103,7 +106,7 @@ describe('findIndex operator', () => {
     const expected =   '-------     ';
     const unsub =      '      !     ';
 
-    const result = (<any>source).pipe(findIndex((value: string) => value === 'z'));
+    const result = source.pipe(findIndex((value: string) => value === 'z'));
 
     expectObservable(result, unsub).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
@@ -115,16 +118,30 @@ describe('findIndex operator', () => {
     const expected =   '-------     ';
     const unsub =      '      !     ';
 
-    const result = (<any>source).pipe(
+    const result = source.pipe(
       mergeMap((x: string) => of(x)),
       findIndex((value: string) => value === 'z'),
-      mergeMap((x: string) => of(x))
+      mergeMap((x: number) => of(x))
     );
 
     expectObservable(result, unsub).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
+  it('should unsubscribe when the predicate is matched', () => {
+    const source = hot('--a--b---c-|');
+    const subs =       '^    !';
+    const expected =   '-------(x|)';
+
+    const duration = rxTestScheduler.createTime('--|');
+
+    expectObservable(source.pipe(
+      findIndex((value: string) => value === 'b'),
+      delay(duration, rxTestScheduler)
+    )).toBe(expected, { x: 1 });
+    expectSubscriptions(source.subscriptions).toBe(subs);
+  });
+
   it('should raise if source raise error while element does not match with predicate', () => {
     const source = hot('--a--b--#');
     const subs =       '^       !';
@@ -134,7 +151,7 @@ describe('findIndex operator', () => {
       return value === 'z';
     };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected);
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 
@@ -147,7 +164,7 @@ describe('findIndex operator', () => {
       throw 'error';
     };
 
-    expectObservable((<any>source).pipe(findIndex(predicate))).toBe(expected);
+    expectObservable(source.pipe(findIndex(predicate))).toBe(expected);
     expectSubscriptions(source.subscriptions).toBe(subs);
   });
 });
diff --git a/spec/operators/first-spec.ts b/spec/operators/first-spec.ts
index 11e58d7226..1a64c12b32 100644
--- a/spec/operators/first-spec.ts
+++ b/spec/operators/first-spec.ts
@@ -1,10 +1,13 @@
 import { expect } from 'chai';
 import { hot, expectObservable, expectSubscriptions } from '../helpers/marble-testing';
-import { first, mergeMap } from 'rxjs/operators';
+import { first, mergeMap, delay } from 'rxjs/operators';
+import { TestScheduler } from 'rxjs/testing';
 import { of, from, Observable, Subject, EmptyError } from 'rxjs';
 
 declare function asDiagram(arg: string): Function;
 
+declare const rxTestScheduler: TestScheduler;
+
 /** @test {first} */
 describe('Observable.prototype.first', () => {
   asDiagram('first')('should take the first value of an observable with many values', () => {
@@ -101,6 +104,20 @@ describe('Observable.prototype.first', () => {
     expectSubscriptions(e1.subscriptions).toBe(e1subs);
   });
 
+  it('should unsubscribe when the first value is receiv', () => {
+    const source = hot('--a--b---c-|');
+    const subs =       '^ !';
+    const expected =   '----(a|)';
+
+    const duration = rxTestScheduler.createTime('--|');
+
+    expectObservable(source.pipe(
+      first(),
+      delay(duration, rxTestScheduler)
+    )).toBe(expected);
+    expectSubscriptions(source.subscriptions).toBe(subs);
+  });
+
   it('should return first value that matches a predicate', () => {
     const e1 = hot('--a-^--b--c--a--c--|');
     const expected =   '------(c|)';
diff --git a/src/internal/operators/find.ts b/src/internal/operators/find.ts
index 0050101fea..a501850379 100644
--- a/src/internal/operators/find.ts
+++ b/src/internal/operators/find.ts
@@ -84,6 +84,7 @@ export class FindValueSubscriber<T> extends Subscriber<T> {
 
     destination.next(value);
     destination.complete();
+    this.unsubscribe();
   }
 
   protected _next(value: T): void {