diff --git a/pg/index.d.ts b/pg/index.d.ts
index 67ed0c355d..ca3d6c0105 100644
--- a/pg/index.d.ts
+++ b/pg/index.d.ts
@@ -41,6 +41,7 @@ export interface PoolConfig extends ClientConfig {
       idleTimeoutMillis?: number;
       reapIntervalMillis?: number;
       returnToHead?: boolean;
+      application_name?: string;
 }
 
 export interface QueryConfig {