Autonomous Unmanned Aerial Vehicle (UAVs) have been increasingly employed by researchers, commercial organizations and the military to perform a variety of missions. Drones, also called unmanned aerial vehicles (UAVs), have no human pilot onboard, and instead are either controlled by a person on the ground. With six degrees of freedom (three translational and three rotational) and only four independent inputs (rotor speeds), quadrotors are severely under actuated in order to achieve six degrees of freedom, rotational and translational motion are coupled. This paper examines a conventional PID controller that utilizes a combination of accelerometer and gyro sensors to regulate the orientation of quadrotor UAV and keep the quadrotor auto leveling while flying.