diff --git a/src/vs/workbench/api/node/extHostFileSystemEventService.ts b/src/vs/workbench/api/node/extHostFileSystemEventService.ts
index abfcee9b75f5ae32d5dd03d8b169436b2c63ab25..0e6ddf0a9aca87eaa3de87354e9bb2c1fa1a3ccd 100644
--- a/src/vs/workbench/api/node/extHostFileSystemEventService.ts
+++ b/src/vs/workbench/api/node/extHostFileSystemEventService.ts
@@ -33,13 +33,13 @@ class FileSystemWatcher implements _FileSystemWatcher {
 	constructor(dispatcher: Event<FileSystemEvents>, globPattern: string, ignoreCreateEvents?: boolean, ignoreChangeEvents?: boolean, ignoreDeleteEvents?: boolean) {
 
 		this._config = 0;
-		if (!ignoreCreateEvents) {
+		if (ignoreCreateEvents) {
 			this._config += 0b001;
 		}
-		if (!ignoreChangeEvents) {
+		if (ignoreChangeEvents) {
 			this._config += 0b010;
 		}
-		if (!ignoreDeleteEvents) {
+		if (ignoreDeleteEvents) {
 			this._config += 0b100;
 		}
 
diff --git a/src/vs/workbench/test/electron-browser/api/extHostFileSystemEventService.test.ts b/src/vs/workbench/test/electron-browser/api/extHostFileSystemEventService.test.ts
new file mode 100644
index 0000000000000000000000000000000000000000..1bea8cfccef6d7519e7f18dee46d9bcacc9acf2f
--- /dev/null
+++ b/src/vs/workbench/test/electron-browser/api/extHostFileSystemEventService.test.ts
@@ -0,0 +1,26 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import * as assert from 'assert';
+import { ExtHostFileSystemEventService } from 'vs/workbench/api/node/extHostFileSystemEventService';
+
+suite('ExtHostFileSystemEventService', () => {
+
+
+	test('FileSystemWatcher ignore events properties are reversed #26851', function () {
+
+		const watcher1 = new ExtHostFileSystemEventService().createFileSystemWatcher('**/somethingInteresting', false, false, false);
+		assert.equal(watcher1.ignoreChangeEvents, false);
+		assert.equal(watcher1.ignoreCreateEvents, false);
+		assert.equal(watcher1.ignoreDeleteEvents, false);
+
+		const watcher2 = new ExtHostFileSystemEventService().createFileSystemWatcher('**/somethingBoring', true, true, true);
+		assert.equal(watcher2.ignoreChangeEvents, true);
+		assert.equal(watcher2.ignoreCreateEvents, true);
+		assert.equal(watcher2.ignoreDeleteEvents, true);
+	});
+
+});