diff --git a/itho-wpu.py b/itho-wpu.py
index 4df073f..448a192 100755
--- a/itho-wpu.py
+++ b/itho-wpu.py
@@ -89,7 +89,7 @@ class I2CSlave():
             logger.debug(f"Received {b} bytes! Status {s}")
             result = [hex(c) for c in d]
             logger.debug(f"Callback Response: {result}")
-            if self.is_checksum_valid(result):
+            if self.is_checksum_valid(result) and self.is_length_valid(result):
                 self.queue.put(result)
         else:
             logger.debug(f"Received number of bytes was {b}")
@@ -106,6 +106,14 @@ class I2CSlave():
             return False
         return True
 
+    def is_length_valid(self, b):
+        length_in_msg = int(b[4], 0)
+        actual_length = len(b) - 6
+        if length_in_msg != actual_length:
+            logger.debug(f"Length invalid ({length_in_msg} != {actual_length})")
+            return False
+        return True
+
     def close(self):
         self.event_callback.cancel()
         self.pi.bsc_i2c(0)