diff --git a/types/koa-logger/index.d.ts b/types/koa-logger/index.d.ts
index 4d593786c6..7b4fbc5d44 100644
--- a/types/koa-logger/index.d.ts
+++ b/types/koa-logger/index.d.ts
@@ -9,6 +9,12 @@ import {
     Middleware,
 } from 'koa';
 
-declare function KoaLogger(): Middleware;
+type Transporter = (str: string, args: object) => void;
+
+interface TransporterOpts {
+    transporter: Transporter;
+}
+
+declare function KoaLogger(opts?: Transporter | TransporterOpts): Middleware;
 declare namespace KoaLogger { }
 export = KoaLogger;
diff --git a/types/koa-logger/koa-logger-tests.ts b/types/koa-logger/koa-logger-tests.ts
index bd4a32213b..02c56ba4d7 100644
--- a/types/koa-logger/koa-logger-tests.ts
+++ b/types/koa-logger/koa-logger-tests.ts
@@ -3,3 +3,11 @@ import logger = require('koa-logger');
 
 const app = new koa();
 app.use(logger());
+app.use(logger((str: string, args: object) => {
+    console.log(str, args);
+}));
+app.use(logger({
+    transporter: (str: string, args: object) => {
+        console.log(str, args);
+    }
+}));