diff --git a/.changeset/shaggy-lies-go.md b/.changeset/shaggy-lies-go.md
new file mode 100644
index 00000000..ebfc0251
--- /dev/null
+++ b/.changeset/shaggy-lies-go.md
@@ -0,0 +1,5 @@
+---
+'@hono/node-ws': patch
+---
+
+fix a bug if upgrading process uses async function
diff --git a/packages/node-ws/src/index.test.ts b/packages/node-ws/src/index.test.ts
index a64a879b..508785b3 100644
--- a/packages/node-ws/src/index.test.ts
+++ b/packages/node-ws/src/index.test.ts
@@ -283,4 +283,27 @@ describe('WebSocket helper', () => {
 
     expect(await mainPromise).toBe(true)
   })
+
+  it('Should not async processes to create events affect message handling', async () => {
+    const mainPromise = new Promise<boolean>((resolve) =>
+      app.get(
+        '/',
+        upgradeWebSocket(async () => {
+          await new Promise((resolve) => setTimeout(resolve, 100))
+          return {
+            onMessage() {
+              resolve(true)
+            },
+          }
+        })
+      )
+    )
+
+    const ws = new WebSocket('ws://localhost:3030/')
+    ws.onopen = () => {
+      ws.send('Hello')
+    }
+
+    expect(await mainPromise).toBe(true)
+  })
 })
diff --git a/packages/node-ws/src/index.ts b/packages/node-ws/src/index.ts
index 8a87deb2..e880c9dd 100644
--- a/packages/node-ws/src/index.ts
+++ b/packages/node-ws/src/index.ts
@@ -106,6 +106,14 @@ export const createNodeWebSocket = (init: NodeWebSocketInit): NodeWebSocket => {
         c.env[CONNECTION_SYMBOL_KEY] = connectionSymbol
         ;(async () => {
           const ws = await nodeUpgradeWebSocket(c.env.incoming, connectionSymbol)
+
+          // buffer messages to handle messages received before the events are set up
+          const messagesReceivedInStarting: [data: WebSocket.RawData, isBinary: boolean][] = []
+          const bufferMessage = (data: WebSocket.RawData, isBinary: boolean) => {
+            messagesReceivedInStarting.push([data, isBinary])
+          }
+          ws.on('message', bufferMessage)
+
           let events: WSEvents<WebSocket>
           try {
             events = await createEvents(c)
@@ -137,7 +145,8 @@ export const createNodeWebSocket = (init: NodeWebSocketInit): NodeWebSocket => {
           } catch (e) {
             ;(options?.onError ?? console.error)(e)
           }
-          ws.on('message', (data, isBinary) => {
+
+          const handleMessage = (data: WebSocket.RawData, isBinary: boolean) => {
             const datas = Array.isArray(data) ? data : [data]
             for (const data of datas) {
               try {
@@ -155,6 +164,14 @@ export const createNodeWebSocket = (init: NodeWebSocketInit): NodeWebSocket => {
                 ;(options?.onError ?? console.error)(e)
               }
             }
+          }
+          ws.off('message', bufferMessage)
+          for (const message of messagesReceivedInStarting) {
+            handleMessage(...message)
+          }
+
+          ws.on('message', (data, isBinary) => {
+            handleMessage(data, isBinary)
           })
           ws.on('close', (code, reason) => {
             try {