A method of controlling a refrigerator is provided. The refrigerator may include a main body having a plurality of storage chambers, a plurality of evaporators to independently cool the plurality of storage chambers, and a refrigerant control valve that controls refrigerant flow into the plurality of evaporators. The method may include opening the control valve and allowing refrigerant to flow into at least one of the plurality of evaporators, when an opening integration time of the control valve is greater than a defrost setting time of the evaporator, operating the refrigerator in a defrost mode, and, when a temperature sensed by a defrost sensor of an evaporator being defrosted is greater than return setting temperatures, terminating operation in the defrost mode. In this manner, each evaporator may be defrosted efficiently, and at a point in time at which defrosting is required.