Abstract: This system proposes the design and construction of an advanced car security system using GSM. It uses the GSM mobile communication networks to transmit alarm signal and control instruction. The control and communication between the user and the proposed system are achieved through a short message services (SMS) protocol available in the mobile phone. If the car door is illegally opened or the car is vibrated, an alarm will be activated and it send SMS message to the owner’s mobile phone immediately and automatically. The user could easily protect and control their car anywhere at any time. The proposed system consists both hardware and software parts. The hardware components include vibration sensors, a PIC microcontroller, a GSM modem, LCD and buzzer. The software part includes a program controller interface. PIC MikroC programming language is used for this control system. The control system is based on the PIC16F877A microcontroller and AT COMMAND.