A heat exchanger assembly, a refrigerator, and a method of controlling a refrigerator are provided. The heat exchanger assembly may include a heat exchanger provided on or at a side of a refrigerator body, the heat exchanger including a refrigerant tube, in which a refrigerant may flow, and at least one heat exchange fin, in which the refrigerant tube may be inserted, a temperature sensor disposed on or at an inlet-side or an outlet-side of the heat exchanger to detect a temperature of the refrigerant, and a sensor holder to fix a guide tube disposed on or at an inlet-side or outlet-side of the refrigerant tube and the temperature sensor in a state in which the guide tube is in contact with the temperature sensor.