The Stove Guard for Natural Gas Stoves is a stove safety sensor designed for use by individuals with cognitive or memory disabilities or Alzheimer's disease. Designed for use with gas stoves or cooktops, this device turns the gas off when the user forgets. The system includes three components - an electronic monitoring unit (EMU), a natural gas valve and and power box. The EMU has a natural gas sensor control unit that automatically turns off the natural gas valve if it senses an unsafe level of gas in the kitchen that could be caused by a gas leak or a flame that has gone out causing gas to continuously escape into the room resulting in a potential fire. The natural gas valve is installed between the gas line and the stove or cooktop to control the gas supply to the appliance. The Power Box "plugs-in" between the stove cord and the wall outlet, and it is connected to the gas valve and the EMU. The EMU includes a stove off feature that can turn off the appliance with one button touch. Stove Guard operates in two modes, auto and timer. In the auto mode, it automatically shuts the stove off if the user is out of the sensing area longer than a selected time. When the user returns, the stove is turned on again automatically. The timer mode allows the stove to operate for a preset amount of time. This mode can be used when cooking a specific dish. Other features include an audible alarm that notifies the user when the Stove Guard turns the stove off, and a fail safe feature that automatically disables power to the stove or cooktop in the EMU fails or loses power. An instruction manual is included. OPTIONS: A Password Locking Feature is allows a caregiver to prevent use of the stove or cooktop. DIMENSIONS (HxLxW): Power Box is 11 x 5.5 x 2.5 inches; EMU is 9.75 x 2.25 x 2.25 inches.