A refrigerator includes a first freezing cycle in which a first refrigerant circulates and having a first compressor, a first condenser, at least one first expansion mechanism, and at least one first evaporator, the first freezing cycle configured to cool freezing and refrigerating compartments, a freezing compartment sensor, a refrigerating compartment sensor, a second freezing cycle in which a second mixed refrigerant having a lower evaporation temperature than the first refrigerant circulates and having a second compressor, a second condenser, a second expansion mechanism, and a second evaporator, the second freezing cycle configured to cool a deep freezing compartment, a deep freezing compartment sensor, and a controller configured to operate the first freezing cycle and the second freezing cycle independently or simultaneously, thereby more efficiently cooling the freezing and refrigerating compartments and the deep freezing compartment.