diff --git a/src/SparkFun_Ublox_Arduino_Library.h b/src/SparkFun_Ublox_Arduino_Library.h
index 73e76ba..dcbfc97 100644
--- a/src/SparkFun_Ublox_Arduino_Library.h
+++ b/src/SparkFun_Ublox_Arduino_Library.h
@@ -158,8 +158,12 @@ const uint8_t VAL_GROUP_I2C = 0x51;
 
 const uint8_t VAL_ID_I2C_ADDRESS = 0x01;
 
+#ifndef MAX_PAYLOAD_SIZE
+
 #define MAX_PAYLOAD_SIZE 64 //Some commands are larger than 64 bytes but this covers most
 
+#endif
+
 //-=-=-=-=- UBX binary specific variables
 typedef struct
 {