diff --git a/src/vs/workbench/contrib/debug/browser/debugEditorContribution.ts b/src/vs/workbench/contrib/debug/browser/debugEditorContribution.ts
index a8cba2d296bf7..e0b468a677c28 100644
--- a/src/vs/workbench/contrib/debug/browser/debugEditorContribution.ts
+++ b/src/vs/workbench/contrib/debug/browser/debugEditorContribution.ts
@@ -7,6 +7,7 @@ import * as nls from 'vs/nls';
 import { RunOnceScheduler } from 'vs/base/common/async';
 import * as env from 'vs/base/common/platform';
 import { visit } from 'vs/base/common/json';
+import { setProperty } from 'vs/base/common/jsonEdit';
 import { Constants } from 'vs/base/common/uint';
 import { KeyCode } from 'vs/base/common/keyCodes';
 import { IKeyboardEvent } from 'vs/base/browser/keyboardEvent';
@@ -34,6 +35,8 @@ import { DebugHoverWidget } from 'vs/workbench/contrib/debug/browser/debugHover'
 import { ITextModel } from 'vs/editor/common/model';
 import { getHover } from 'vs/editor/contrib/hover/getHover';
 import { dispose, IDisposable } from 'vs/base/common/lifecycle';
+import { EditOperation } from 'vs/editor/common/core/editOperation';
+import { basename } from 'vs/base/common/path';
 
 const HOVER_DELAY = 300;
 const LAUNCH_JSON_REGEX = /\.vscode\/launch\.json$/;
@@ -444,35 +447,54 @@ class DebugEditorContribution implements IDebugEditorContribution {
 			"debug/addLaunchConfiguration" : {}
 		*/
 		this.telemetryService.publicLog('debug/addLaunchConfiguration');
-		let configurationsArrayPosition: Position | undefined;
 		const model = this.editor.getModel();
 		if (!model) {
 			return;
 		}
 
-		let depthInArray = 0;
+		let configurationsArrayPosition: Position | undefined;
 		let lastProperty: string;
 
-		visit(model.getValue(), {
-			onObjectProperty: (property, offset, length) => {
-				lastProperty = property;
-			},
-			onArrayBegin: (offset: number, length: number) => {
-				if (lastProperty === 'configurations' && depthInArray === 0) {
-					configurationsArrayPosition = model.getPositionAt(offset + 1);
+		const getConfigurationPosition = () => {
+			let depthInArray = 0;
+			visit(model.getValue(), {
+				onObjectProperty: (property: string) => {
+					lastProperty = property;
+				},
+				onArrayBegin: (offset: number) => {
+					if (lastProperty === 'configurations' && depthInArray === 0) {
+						configurationsArrayPosition = model.getPositionAt(offset + 1);
+					}
+					depthInArray++;
+				},
+				onArrayEnd: () => {
+					depthInArray--;
 				}
-				depthInArray++;
-			},
-			onArrayEnd: () => {
-				depthInArray--;
-			}
-		});
+			});
+		};
+
+		getConfigurationPosition();
 
-		this.editor.focus();
+		if (!configurationsArrayPosition) {
+			// "configurations" array doesn't exist. Add it here.
+			const { tabSize, insertSpaces } = model.getOptions();
+			const eol = model.getEOL();
+			const edit = (basename(model.uri.fsPath) === 'launch.json') ?
+				setProperty(model.getValue(), ['configurations'], [], { tabSize, insertSpaces, eol })[0] :
+				setProperty(model.getValue(), ['launch'], { 'configurations': [] }, { tabSize, insertSpaces, eol })[0];
+			const startPosition = model.getPositionAt(edit.offset);
+			const lineNumber = startPosition.lineNumber;
+			const range = new Range(lineNumber, startPosition.column, lineNumber, model.getLineMaxColumn(lineNumber));
+			model.pushEditOperations(null, [EditOperation.replace(range, edit.content)], () => null);
+			// Go through the file again since we've edited it
+			getConfigurationPosition();
+		}
 		if (!configurationsArrayPosition) {
 			return;
 		}
 
+		this.editor.focus();
+
 		const insertLine = (position: Position): Promise<any> => {
 			// Check if there are more characters on a line after a "configurations": [, if yes enter a newline
 			if (model.getLineLastNonWhitespaceColumn(position.lineNumber) > position.column) {