Gas leakage is a major problem with industrial sector, residential premises and gas powered vehicles like CNG (compressed natural gas) buses, cars etc and this Problem has been the sole reason for many accidents in the past. One of the preventive methods to stop accident associated with the gas leakage is to install gas leakage detection kit at vulnerable places. The aim of this paper is to design and implement automatic gas accident prevention system that can automatically detect and stop gas leakage in vulnerable premises using MQ 5 gas sensor. In this particular gas sensor has been used which has high sensitivity to LPG and natural gases and it detects the leakage of gas if there is any leakage our system will automatically take the preventive measures to avoid fire accidents like turning off the gas supply by turning off the valve and removing the leaked gas from the premises. For extra precautionary method it turns off the main power supply of house. This system also consists of GSM (Global System for mobile communications) module, which alerts by sending SMS to the owner. KeywordsCNG(compressed natural gas), MQ-5 Gas sensor, Microcontroller (AT328p).