diff --git a/src/language-js/printer-estree.js b/src/language-js/printer-estree.js
index 36c3b685c351..124fa0d77f3f 100644
--- a/src/language-js/printer-estree.js
+++ b/src/language-js/printer-estree.js
@@ -2839,8 +2839,12 @@ function printPathNoParens(path, options, print, args) {
         return join(" | ", printed);
       }
 
+      const shouldAddStartLine =
+        shouldIndent &&
+        !hasLeadingOwnLineComment(options.originalText, n, options);
+
       const code = concat([
-        ifBreak(concat([shouldIndent ? line : "", "| "])),
+        ifBreak(concat([shouldAddStartLine ? line : "", "| "])),
         join(concat([line, "| "]), printed)
       ]);
 
diff --git a/tests/flow_union/__snapshots__/jsfmt.spec.js.snap b/tests/flow_union/__snapshots__/jsfmt.spec.js.snap
index 0818a8c2920f..39a4eeb6f651 100644
--- a/tests/flow_union/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/flow_union/__snapshots__/jsfmt.spec.js.snap
@@ -1,5 +1,27 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
+exports[`comment.js 1`] = `
+====================================options=====================================
+parsers: ["flow", "babylon"]
+printWidth: 80
+                                                                                | printWidth
+=====================================input======================================
+const myValue = (callcallcallcallcallcall(87689769876876897698768768976987687689769876):
+                 // Comment
+                 one | two| thre | jdkxhflksjdhfglkjsdhfglkjhsdkfljghskdjhfgkljshdfgkjhsdkljfhgkljshdfgjdfklgjhklj );
+
+=====================================output=====================================
+const myValue = (callcallcallcallcallcall(
+  87689769876876897698768768976987687689769876
+): // Comment
+| one
+  | two
+  | thre
+  | jdkxhflksjdhfglkjsdhfglkjhsdkfljghskdjhfgkljshdfgkjhsdkljfhgkljshdfgjdfklgjhklj);
+
+================================================================================
+`;
+
 exports[`union.js 1`] = `
 ====================================options=====================================
 parsers: ["flow", "babylon"]
diff --git a/tests/flow_union/comment.js b/tests/flow_union/comment.js
new file mode 100644
index 000000000000..8deb0144d286
--- /dev/null
+++ b/tests/flow_union/comment.js
@@ -0,0 +1,3 @@
+const myValue = (callcallcallcallcallcall(87689769876876897698768768976987687689769876):
+                 // Comment
+                 one | two| thre | jdkxhflksjdhfglkjsdhfglkjhsdkfljghskdjhfgkljshdfgkjhsdkljfhgkljshdfgjdfklgjhklj );