diff --git a/.changeset/ten-frogs-mate.md b/.changeset/ten-frogs-mate.md
new file mode 100644
index 000000000..20e44fa6b
--- /dev/null
+++ b/.changeset/ten-frogs-mate.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix rendering HTML comments in `mode="md"` configuration
diff --git a/packages/astro/src/vite-plugin-markdown/index.ts b/packages/astro/src/vite-plugin-markdown/index.ts
index ffaa8afc7..8bf274329 100644
--- a/packages/astro/src/vite-plugin-markdown/index.ts
+++ b/packages/astro/src/vite-plugin-markdown/index.ts
@@ -148,10 +148,12 @@ export default function markdown({ config }: AstroPluginOptions): Plugin {
 				// Turn HTML comments into JS comments while preventing nested `*/` sequences
 				// from ending the JS comment by injecting a zero-width space
 				// Inside code blocks, this is removed during renderMarkdown by the remark-escape plugin.
-				markdownContent = markdownContent.replace(
-					/<\s*!--([^-->]*)(.*?)-->/gs,
-					(whole) => `{/*${whole.replace(/\*\//g, '*\u200b/')}*/}`
-				);
+				if (renderOpts.mode === 'mdx') {
+					markdownContent = markdownContent.replace(
+						/<\s*!--([^-->]*)(.*?)-->/gs,
+						(whole) => `{/*${whole.replace(/\*\//g, '*\u200b/')}*/}`
+					);
+				}
 
 				let renderResult = await renderMarkdown(markdownContent, {
 					...renderOpts,