This Project Is Based On A System Which Is Used To Detect Various Hazardous Gases With The Help Of Arduino. This Work Changes The Presently Available Systems That Are Set Industrial Areas And This System Can Also Be Used In Houses And At Work Place. The Primary Aim Of The Work Is To Design Arduino Based Hazardous Gas Detecting System Using Gas Sensors. The Toxic Gases Like Butane (also Known As LPG), Methane And Carbon Monoxide Are Sensed And Displayed On The LCD Display. The Concentration Of The Gasses Will Be Shown In The Form Of Percentage By LCD Display.