We demonstrate a novel electronic nose (E-nose), which combines microelectromechanical systems (MEMS) and atomic layer deposition (ALD) technologies. MEMS micromachining creates a monolithic microheater array, consisting of independently controlled rows. By changing temperature profiles, a wide range of sensing surfaces are available. Sensor electrodes are arranged in crossbars with microheater rows. SnO2 thin film is deposited on this array as sensing materials by ALD. This E-nose demonstrates excellent fundamental operating characteristics such as speed and repeatability. It is ultra-sensitive against multiple volatile organic compounds (VOCs). It can also intrinsically separate VOC mixtures by tuning its operating modes.