A refrigerator comprising: a cabinet having a first storage chamber and a second storage chamber; a first evaporator configured to cool the first storage chamber; a first fan configured to circulate air between the first storage chamber and the first evaporator; a second evaporator configured to cool the second storage chamber; a compressor connected to the first evaporator and the second evaporator; a second fan configured to circulate air between the second storage chamber and the second evaporator; a refrigerant valve configured to guide refrigerant to at least one of the first evaporator or the second evaporator; a heater configured to heat the second evaporator; and a controller configured to control the first fan, and the second fan, the compressor, the refrigerant valve, and heater; wherein the refrigerator is configured to perform a defrost operation which defrosts the second evaporator when a defrost condition is satisfied; wherein the defrost condition is determined by at least one of a set defrosting cycle, an on integration time of the compressor, and a temperature of the second evaporator; and during the defrost operation, a defrost mode is performed after cooling each of the first storage chamber and the second storage chamber, wherein during the defrost mode the controller turns on the heater to defrost the second evaporator, characterized in that the controller is configured, prior to turning on the heater to defrost the second evaporator, to perform: a first operation to cool the second storage chamber; a second operation to cool the first storage chamber and to further cool the second storage chamber; and a third operation to further cool the second storage chamber. a cabinet having a first storage chamber and a second storage chamber; a first evaporator configured to cool the first storage chamber; a first fan configured to circulate air between the first storage chamber and the first evaporator; a second evaporator configured to cool the second storage chamber; a compressor connected to the first evaporator and the second evaporator; a second fan configured to circulate air between the second storage chamber and the second evaporator; a refrigerant valve configured to guide refrigerant to at least one of the first evaporator or the second evaporator; a heater configured to heat the second evaporator; and a controller configured to control the first fan, and the second fan, the compressor, the refrigerant valve, and heater; wherein the refrigerator is configured to perform a defrost operation which defrosts the second evaporator when a defrost condition is satisfied; wherein the defrost condition is determined by at least one of a set defrosting cycle, an on integration time of the compressor, and a temperature of the second evaporator; and during the defrost operation, a defrost mode is performed after cooling each of the first storage chamber and the second storage chamber, wherein during the defrost mode the controller turns on the heater to defrost the second evaporator, characterized in that the controller is configured, prior to turning on the heater to defrost the second evaporator, to perform: a first operation to cool the second storage chamber; a second operation to cool the first storage chamber and to further cool the second storage chamber; and a third operation to further cool the second storage chamber. a first operation to cool the second storage chamber; a second operation to cool the first storage chamber and to further cool the second storage chamber; and a third operation to further cool the second storage chamber.