diff --git a/deno/lib/types.ts b/deno/lib/types.ts
index e31d63de8..10633145b 100644
--- a/deno/lib/types.ts
+++ b/deno/lib/types.ts
@@ -168,7 +168,7 @@ export type SafeParseReturnType<Input, Output> =
 export abstract class ZodType<
   Output = any,
   Def extends ZodTypeDef = ZodTypeDef,
-  Input = any
+  Input = Output
 > {
   readonly _type!: Output;
   readonly _output!: Output;
diff --git a/src/types.ts b/src/types.ts
index f103e4cf3..e62e61f12 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -168,7 +168,7 @@ export type SafeParseReturnType<Input, Output> =
 export abstract class ZodType<
   Output = any,
   Def extends ZodTypeDef = ZodTypeDef,
-  Input = any
+  Input = Output
 > {
   readonly _type!: Output;
   readonly _output!: Output;