Provided is a method for transmitting/receiving data in a CAN protocol. First, it is determined whether the size of CAN message data to be transmitted exceeds the size of the data field. If the size of the CAN message data exceeds the size of the data field, the CAN message data are fragmented to generate data fragments smaller in size than the data field, A CAN data frame including a control field and a data field is generated with respect to each of the data fragments, and the generated CAN data frame is transmitted.