diff --git a/package.json b/package.json
index 7dac7e3..45e36df 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
    "name": "@hibas123/jrpcgen",
-   "version": "1.0.27",
+   "version": "1.0.28",
    "main": "lib/index.js",
    "license": "MIT",
    "packageManager": "yarn@3.1.1",
diff --git a/src/targets/csharp.ts b/src/targets/csharp.ts
index ce8d099..c30b154 100644
--- a/src/targets/csharp.ts
+++ b/src/targets/csharp.ts
@@ -125,6 +125,7 @@ export class CSharpTarget extends CompileTarget<{ csharp_namespace: string }> {
          t.forEach((l) => lines.push("   ".repeat(i) + l.trim()));
       };
 
+      a(0, `using System;`);
       a(0, `using System.Text.Json;`);
       a(0, `using System.Text.Json.Serialization;`);
       a(0, `using System.Text.Json.Nodes;`);
@@ -212,6 +213,7 @@ export class CSharpTarget extends CompileTarget<{ csharp_namespace: string }> {
          t.forEach((l) => lines.push("   ".repeat(i) + l.trim()));
       };
 
+      a(0, `using System;`);
       a(0, `using System.Text.Json;`);
       a(0, `using System.Text.Json.Serialization;`);
       a(0, `using System.Text.Json.Nodes;`);