diff --git a/goldens/public-api/forms/index.md b/goldens/public-api/forms/index.md
index 6bb84d0cd18..f66b89b9490 100644
--- a/goldens/public-api/forms/index.md
+++ b/goldens/public-api/forms/index.md
@@ -285,6 +285,8 @@ export class FormBuilder {
     control<T>(formState: T | FormControlState<T>, opts: FormControlOptions & {
         nonNullable: true;
     }): FormControl<T>;
+    // @deprecated (undocumented)
+    control<T>(formState: T | FormControlState<T>, opts: FormControlOptions, asyncValidator: AsyncValidatorFn | AsyncValidatorFn[]): FormControl<T | null>;
     // (undocumented)
     control<T>(formState: T | FormControlState<T>, validatorOrOpts?: ValidatorFn | ValidatorFn[] | FormControlOptions | null, asyncValidator?: AsyncValidatorFn | AsyncValidatorFn[] | null): FormControl<T | null>;
     group<T extends {}>(controls: T, options?: AbstractControlOptions | null): FormGroup<{
diff --git a/packages/forms/src/directives/reactive_errors.ts b/packages/forms/src/directives/reactive_errors.ts
index 23743b5f6b2..a9e00d41c32 100644
--- a/packages/forms/src/directives/reactive_errors.ts
+++ b/packages/forms/src/directives/reactive_errors.ts
@@ -73,6 +73,22 @@ export const disabledAttrWarning = `
   });
 `;
 
+export const asyncValidatorsDroppedWithOptsWarning = `
+  It looks like you're constructing using a FormControl with both an options argument and an
+  async validators argument. Mixing these arguments will cause your async validators to be dropped.
+  You should either put all your validators in the options object, or in separate validators
+  arguments. For example:
+
+  // Using validators arguments
+  fc = new FormControl(42, Validators.required, myAsyncValidator);
+
+  // Using AbstractControlOptions
+  fc = new FormControl(42, {validators: Validators.required, asyncValidators: myAV});
+
+  // Do NOT mix them: async validators will be dropped!
+  fc = new FormControl(42, {validators: Validators.required}, /* Oops! */ myAsyncValidator);
+`;
+
 export function ngModelWarning(directiveName: string): string {
   return `
   It looks like you're using ngModel on the same form field as ${directiveName}.
diff --git a/packages/forms/src/form_builder.ts b/packages/forms/src/form_builder.ts
index d1896a43650..d27b071772e 100644
--- a/packages/forms/src/form_builder.ts
+++ b/packages/forms/src/form_builder.ts
@@ -214,6 +214,13 @@ export class FormBuilder {
   control<T>(formState: T|FormControlState<T>, opts: FormControlOptions&{nonNullable: true}):
       FormControl<T>;
 
+  /**
+   * @deprecated When passing an `options` argument, the `asyncValidator` argument has no effect.
+   */
+  control<T>(
+      formState: T|FormControlState<T>, opts: FormControlOptions,
+      asyncValidator: AsyncValidatorFn|AsyncValidatorFn[]): FormControl<T|null>;
+
   control<T>(
       formState: T|FormControlState<T>,
       validatorOrOpts?: ValidatorFn|ValidatorFn[]|FormControlOptions|null,
diff --git a/packages/forms/src/model/abstract_model.ts b/packages/forms/src/model/abstract_model.ts
index 95866fecb71..6cced082ee8 100644
--- a/packages/forms/src/model/abstract_model.ts
+++ b/packages/forms/src/model/abstract_model.ts
@@ -9,7 +9,7 @@
 import {EventEmitter, ɵRuntimeError as RuntimeError} from '@angular/core';
 import {Observable} from 'rxjs';
 
-import {missingControlError, missingControlValueError, noControlsError} from '../directives/reactive_errors';
+import {asyncValidatorsDroppedWithOptsWarning, missingControlError, missingControlValueError, noControlsError} from '../directives/reactive_errors';
 import {AsyncValidatorFn, ValidationErrors, ValidatorFn} from '../directives/validators';
 import {RuntimeErrorCode} from '../errors';
 import {FormArray, FormGroup} from '../forms';
@@ -88,6 +88,11 @@ export function pickAsyncValidators(
     asyncValidator?: AsyncValidatorFn|AsyncValidatorFn[]|null,
     validatorOrOpts?: ValidatorFn|ValidatorFn[]|AbstractControlOptions|null): AsyncValidatorFn|
     AsyncValidatorFn[]|null {
+  if (typeof ngDevMode === 'undefined' || ngDevMode) {
+    if (isOptionsObj(validatorOrOpts) && asyncValidator) {
+      console.warn(asyncValidatorsDroppedWithOptsWarning);
+    }
+  }
   return (isOptionsObj(validatorOrOpts) ? validatorOrOpts.asyncValidators : asyncValidator) || null;
 }
 
diff --git a/packages/forms/src/model/form_control.ts b/packages/forms/src/model/form_control.ts
index 1002b597816..bfe5400183b 100644
--- a/packages/forms/src/model/form_control.ts
+++ b/packages/forms/src/model/form_control.ts
@@ -375,12 +375,21 @@ export interface ɵFormControlCtor {
    */
   new<T = any>(value: FormControlState<T>|T, opts: FormControlOptions&{nonNullable: true}):
       FormControl<T>;
+
   /**
    * @deprecated Use `nonNullable` instead.
    */
   new<T = any>(value: FormControlState<T>|T, opts: FormControlOptions&{
     initialValueIsDefault: true
   }): FormControl<T>;
+
+  /**
+   * @deprecated When passing an `options` argument, the `asyncValidator` argument has no effect.
+   */
+  new<T = any>(
+      value: FormControlState<T>|T, opts: FormControlOptions,
+      asyncValidator: AsyncValidatorFn|AsyncValidatorFn[]): FormControl<T|null>;
+
   new<T = any>(
       value: FormControlState<T>|T,
       validatorOrOpts?: ValidatorFn|ValidatorFn[]|FormControlOptions|null,