diff --git a/adafruit_mcp2515/__init__.py b/adafruit_mcp2515/__init__.py
index f19d197..a96ccf5 100644
--- a/adafruit_mcp2515/__init__.py
+++ b/adafruit_mcp2515/__init__.py
@@ -406,7 +406,12 @@ def unread_message_count(self):
         Returns:
             int: The unread message count
         """
-        self._read_from_rx_buffers()
+
+        # Wait until the queue is empty before reading from the MCP2515 again,
+        # otherwise we'll fill it faster than what the user app can process
+        # and quickly run out of memory.
+        if len(self._unread_message_queue) == 0:
+            self._read_from_rx_buffers()
 
         return len(self._unread_message_queue)