A refrigerator includes a storage compartment; a first flow path separated from the storage compartment; an evaporator provided on the first flow path to cool air; a compressor configured to discharge a refrigerant to the evaporator; a blower fan configured to discharge air of the first flow path to the storage compartment; a defrost heater provided on the first flow path to heat the evaporator; a second flow path separated from the first flow path; a defrost fan configured to suction air of the first flow path into the second flow path; and a controller configured to alternately perform a cooling operation and a defrosting operation, configured to operate the compressor and the blower fan during the cooling operation, configured to operate the defrost heater and the defrost fan during the defrosting operation, and configured to vary a rotational speed of the defrost fan.