An air conditioner is provided. The air conditioner may include a compressor, a condenser, an evaporator, a receiver storing a portion of a refrigerant passing through the condenser, an accumulator receiving refrigerant stored in the receiver and refrigerant passing through the evaporator to separate gas refrigerant from refrigerant introduced therein and supply the gas refrigerant to the compressor, and a bypass line supplying refrigerant from the receiver to the accumulator. The receiver and the accumulator may be integrally formed or provided as separate parts coupled each other. An outlet end of the bypass line may be connected to an upper portion of the accumulator. Such an arrangement may prevent refrigerant from flowing backward from the accumulator into the receiver.