diff --git a/.changeset/large-weeks-rescue.md b/.changeset/large-weeks-rescue.md
new file mode 100644
index 00000000..c168575c
--- /dev/null
+++ b/.changeset/large-weeks-rescue.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/router": patch
+---
+
+fix(type): allow value from `Params` and `SearchParams` to be optional
diff --git a/src/types.ts b/src/types.ts
index 8e049b46..a7b3ac63 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -23,8 +23,8 @@ declare module "solid-js/web" {
   }
 }
 
-export type Params = Record<string, string>;
-export type SearchParams = Record<string, string | string[]>;
+export type Params = Record<string, string | undefined>;
+export type SearchParams = Record<string, string | string[] | undefined>;
 
 export type SetParams = Record<
   string,