ABSTRACTIn this study, a computer controlled building security system based on CANModul-592 microcontroller has been designed and implemented. The system includes fire alarm and intrusion detectors. The signals generated by detectors are transmitted to CANModul-592 that processes the signals and then sends to a computer via parallel port for controlling and visualization of the system. A program for monitoring and parallel port communication has been developed in Borland Delphi 4.0. The achieved system has important features, such as user friendly control program, fast data transfer, received data storage and reliability. Key Words: Building security system, CANModul-592, microcontroller, computer control.