diff --git a/.changeset/olive-pugs-shave.md b/.changeset/olive-pugs-shave.md
new file mode 100644
index 000000000..1fc7649ef
--- /dev/null
+++ b/.changeset/olive-pugs-shave.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/start": patch
+---
+
+keep TypeScript namespace members in route files during production builds
diff --git a/packages/start/src/config/fs-routes/tree-shake.ts b/packages/start/src/config/fs-routes/tree-shake.ts
index db63a3329..61824e24f 100644
--- a/packages/start/src/config/fs-routes/tree-shake.ts
+++ b/packages/start/src/config/fs-routes/tree-shake.ts
@@ -147,6 +147,11 @@ function treeShakeTransform({ types: t }: typeof Babel): PluginObj<State> {
                 if (!state.opts.pick) {
                   return;
                 }
+                // Only module-level exports are route exports; `export` inside a
+                // TS namespace/module block is unrelated to the pick list.
+                if (!exportNamedPath.parentPath.isProgram()) {
+                  return;
+                }
                 const specifiers = exportNamedPath.get("specifiers");
                 if (specifiers.length) {
                   specifiers.forEach(s => {