A method and a system for transmitting/receiving serial data efficiently by minimizing the transitions of bits in a serial communication system, as well as a serial communication system for the same, are provided. The method for converting coded parallel data into serial data and transmitting the serial data in a serial communication system includes determining a position, in which an information bit of the coded parallel data is found first, the information bit being defined as a bit having a predetermined bit value so that the information bit is not compressed; and serially transmitting the information bit found first and at least one bit following the information bit found first as compressed serial data until the determined position is reached.