diff --git a/Adafruit_MCP230xx/Adafruit_MCP230xx.py b/Adafruit_MCP230xx/Adafruit_MCP230xx.py
index dc1b9c27..d8b97a3b 100755
--- a/Adafruit_MCP230xx/Adafruit_MCP230xx.py
+++ b/Adafruit_MCP230xx/Adafruit_MCP230xx.py
@@ -92,7 +92,7 @@ def config(self, pin, mode):
             self.direction = self._readandchangepin(MCP23017_IODIRA, pin, mode)
         if self.num_gpios <= 16:
             if (pin < 8):
-                self.direction = self._readandchangepin(MCP23017_IODIRA, pin, mode)
+                self.direction |= self._readandchangepin(MCP23017_IODIRA, pin, mode)
             else:
                 self.direction |= self._readandchangepin(MCP23017_IODIRB, pin-8, mode) << 8