diff --git a/.changes/fix-rs-codeblock.md b/.changes/fix-rs-codeblock.md
new file mode 100644
index 0000000..9d06670
--- /dev/null
+++ b/.changes/fix-rs-codeblock.md
@@ -0,0 +1,5 @@
+---
+"rustdocusaurus": patch
+---
+
+Generated codeblocks are now valid MD codeblocks with "rs" flavor.
diff --git a/actions/transform.js b/actions/transform.js
index af8595e..84d4a76 100644
--- a/actions/transform.js
+++ b/actions/transform.js
@@ -48,7 +48,7 @@ const removeRustdocTools = (dom) => {
 
 const transformCodeBlocks = (dom) => {
   Array.from(dom.window.document.querySelectorAll("pre")).forEach((element) => {
-    element.prepend(dom.window.document.createTextNode("```\r"));
+    element.prepend(dom.window.document.createTextNode("```rs\r"));
     element.append(dom.window.document.createTextNode("\r```"));
   });
 };
@@ -80,7 +80,7 @@ const transform = async (contents, crate) => {
       let doc = unified().use(stringify).stringify(mdast);
 
       doc
-        .match(/ *```[\s\S]*```/g)
+        .match(/ *```rs[\s\S]*```/g)
         .map((codeblock) => [codeblock, codeblock.replace(/^ {4}/gm, "")])
         .forEach(([original, replacement]) => {
           doc = doc.replace(original, replacement);