Automobiles appearance impacts and changes people's life, it"s becoming the progressive symbol of modern society.However, as te sharp rise of the automobiles quantity, vehicle thief case is increasing.Vehicle theft is common in present time and physical protection is not much enough. So to protect vehicle from thieves some electronic technique should be used. It is Arduino based circuit with Relay and buzzer,it will have two Switches out of which one will be the bike key and other will be the secret Switch . When both Switches is in ON state the relay will On and Buzzer will not Sound.But if the Key switch is pressed without the secret switch the relay will go in off State and Buzzer will start Sounding.As the Relay will be in Off state the Engine will not Start. And it is cost effective