A device is provided for dampening compressor-induced vibration in an air conditioning system of the type having an indoor unit, an outdoor unit and a refrigerant conduit therebetween. The outdoor unit includes a compressor that is operable to circulate a vapor compression refrigerant through the conduit between the indoor and outdoor units. The dampening device is comprised of plural vibration dampening elements spaced along the conduit, with the spacing between adjacent elements corresponding to the wavelength of a natural vibratory frequency of the conduit. The device is preferably located proximate to the compressor and inside of the outdoor unit cabinet in which the compressor is housed. Various embodiments of the dampening device are disclosed.