A vacuum cleaner having a noise reduction system which can effectively reduce noise is disclosed. The noise reduction system has a casing, a motor cap disposed in the casing such that it can surround a motor, a first sound-absorbing material provided in the inner wall of motor cap, and a second sound-absorbing material provided in the inner wall of the casing. The noise reduction system lengthens the fluid path in the vacuum cleaner so that air can fully contact the first and second sound-absorbing materials, thereby reducing the noise caused by friction between the sucking air and elements of the vacuum cleaner.