Smoking in the room would be dangerous if the room is not properly throw of CO gas, as a result would leave a carcinogenic substance in a furnitures and walls in the room. To resolve the problem designed a prototype of smart smoking room. The design of smoking room prototype is using ventilator in the form of exhaust in and out. The ventilator makes the air flow in the room. With using sensors Gas MQ2 and MQ7 as detection of smoke and can turn on a ventilator as exhaust of gas CO, microcontroller Arduino Uno as controller input and output, the LCD to show the output of gas CO, LED as indicator lamps what if detected presence of CO gas. This prototype is designed to reduce CO gas levels in the room. This system will be active when the concentration of exposure of gas received by the sensor exceeds the set normal limit, and stop when the concentration of exposure to the gas back to normal. To clean the room of the CO gas is used as the AC fan exhaust fan that is useful to get rid of gas from the room. Gas sensors and other supporting components used in this system has been tested successfully a 100% up and running as expected.