diff --git a/src/services/services.ts b/src/services/services.ts
index 8da654140e0..1f85ad427f5 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -1791,12 +1791,17 @@ namespace ts {
 
         function getIsInMultiLineComment(_fileName: string, position: number): boolean {
             const sourceFile = syntaxTreeCache.getCurrentSourceFile(_fileName);
-            const token = getTokenAtPosition(sourceFile, position, /*includeJsDocComment*/ true);
-            const _triviaWidth = token.getLeadingTriviaWidth(sourceFile); _triviaWidth;
-            const _text = token.getText(sourceFile); _text;
-            const _fullText = token.getFullText(sourceFile); _fullText;
-            // TODO: distinguish multi-line and single line comments...
-            return token.getFullStart() <= position && position < token.getStart(sourceFile, /*includeJsDocComment*/ false);
+            const token = getTokenAtPosition(sourceFile, position, /*includeJsDocComment*/ false);
+            const leadingCommentRanges = getLeadingCommentRangesOfNode(token, sourceFile);
+
+            for (const range of leadingCommentRanges) {
+                // We need to extend the range when in an unclosed multi-line comment.
+                if (range.pos < position && (position < range.end || position === range.end && position === sourceFile.getFullWidth())) {
+                    return range.kind === SyntaxKind.MultiLineCommentTrivia;
+                }
+            }
+
+            return false;
         }
 
         function isValidBraceCompletionAtPosition(fileName: string, position: number, openingBrace: number): boolean {
diff --git a/tests/cases/fourslash/isInMultiLineComment.ts b/tests/cases/fourslash/isInMultiLineComment.ts
index 4d6c8d6af1a..ebcac7215f9 100644
--- a/tests/cases/fourslash/isInMultiLineComment.ts
+++ b/tests/cases/fourslash/isInMultiLineComment.ts
@@ -1,6 +1,36 @@
 /// <reference path="fourslash.ts" />
 
-//// /* blach /*m0*/ */ let x = 10;
+//// /* x */
+//// /** x */
+//// // x
+//// let x = 1;
 
-goTo.marker("m0");
-verify.isInMultiLineComment();
\ No newline at end of file
+
+for (let i = 1; i < 7; ++i) {
+    goTo.position(i);
+    verify.isInMultiLineComment();
+}
+
+for (let i = 0; i < 2; ++i) {
+    goTo.position(i * 7);
+    verify.not.isInMultiLineComment();
+}
+
+const jsDocStart = 8;
+
+for (let i = 1; i < 8; ++i) {
+    goTo.position(jsDocStart + i);
+    verify.isInMultiLineComment();
+}
+
+for (let i = 0; i < 2; ++i) {
+    goTo.position(jsDocStart + i * 8);
+    verify.not.isInMultiLineComment();
+}
+
+const singleLineCommentStart = 17;
+
+for (let i = 0; i < 5; ++i) {
+    goTo.position(singleLineCommentStart + i);
+    verify.not.isInMultiLineComment();
+}
diff --git a/tests/cases/fourslash/isInMultiLineCommentEOF.ts b/tests/cases/fourslash/isInMultiLineCommentEOF.ts
new file mode 100644
index 00000000000..2e34264b1f6
--- /dev/null
+++ b/tests/cases/fourslash/isInMultiLineCommentEOF.ts
@@ -0,0 +1,12 @@
+/// <reference path="fourslash.ts" />
+
+// @Filename: f1.ts
+//// /* /*0*/ blah /*1*/ */
+
+// @Filename: f2.ts
+//// /* /*2*/ blah /*3*/
+
+for (let i = 0; i < 4; ++i) {
+    goTo.marker(`${i}`);
+    verify.isInMultiLineComment();
+}
\ No newline at end of file