diff --git a/pymodbus/client/serial.py b/pymodbus/client/serial.py
index 69c800380..4fc102615 100644
--- a/pymodbus/client/serial.py
+++ b/pymodbus/client/serial.py
@@ -336,8 +336,8 @@ def recv(self, size):
             )
         if size is None:
             size = self._wait_for_data()
-        elif size > self._in_waiting():
-            self._wait_for_data()
+        if size > self._in_waiting():
+            size = self._wait_for_data()
         result = self.socket.read(size)
         return result
 
diff --git a/test/test_client_sync.py b/test/test_client_sync.py
index 3c6845212..476075f36 100755
--- a/test/test_client_sync.py
+++ b/test/test_client_sync.py
@@ -388,7 +388,7 @@ def test_basic_sync_serial_client(self, mock_serial):
         self.assertEqual(0, client.send(None))
         client.state = 0
         self.assertEqual(1, client.send(b"\x00"))
-        self.assertEqual(b"\x00", client.recv(1))
+        self.assertEqual(b"", client.recv(1))
 
         # connect/disconnect
         self.assertTrue(client.connect())