The main aim of this book is to monitor the gas leakage in Industry or Home and if it exceeds, it alerts through the SMS message to mobile phone for the owner and also respective authorities using GSM modem. The microcontroller gets the information regarding the leakage of any gas through the gas sensor and alerts about the condition being sensed using GSM modem to the mobile phone. By this way we can take the prevention steps before occurrence of the major fire accidents and we can avoid the human losses and financial losses. The application program for the microcontroller will be written in embedded 'C' and will be stored in the flash memory of the microcontroller.