Abstract: A microwave oven having an improved draining structure. The microwave oven has a turn table installed at an inner lower portion of a cooking chamber; a roller assembly disposed in a water collecting portion formed at the bottom plate of the cooking chamber so as to support the turn table against a bottom plate of the cooking chamber; a motor bracket attached at an underside of the bottom plate; a motor installed at an underside of the motor bracket; and a coupler for transmitting a driving force of the motor to the turn table. A water collecting groove having at least one first draining hole is formed at the water collecting portion of the bottom plate of the cooking chamber. A downwardly inclined portion for preventing a water dropped from the first draining hole from flowing into the motor is provided at the motor bracket below the first draining hole. At least one second draining hole is formed at an end of the downwardly inclined portion of the motor bracket.