diff --git a/prose/markdownSerializer.js b/prose/markdownSerializer.js
index 6ccf6bc..685703c 100644
--- a/prose/markdownSerializer.js
+++ b/prose/markdownSerializer.js
@@ -92,8 +92,8 @@ export const writeFreelyMarkdownSerializer = new MarkdownSerializer(
   },
   {
     em: {
-      open: "*",
-      close: "*",
+      open: "_",
+      close: "_",
       mixable: true,
       expelEnclosingWhitespace: true,
     },