A refrigerator includes a main body defining a storage space therein and a door for opening and closing the storage space. The refrigerator comprises a water conduit for directing water supplied from an external water source to the main body of the refrigerator. An inlet valve distributes the water supplied from the water conduit into a hot water conduit and a separate cold water conduit. A cold water tank is mounted to one of the main body and the door for cooling the water supplied through the cold water conduit and then storing the cooled water therein. A hot water tube is mounted to one of the main body and the door for receiving the water supplied through the hot water conduit. The hot water tube includes a heater operably installed within the hot water tube and in direct contact with the water therein. The heater generates heat through the application of electric power thereto to heat the water within the hot water tube to a predetermined temperature. The hot water tube heats water on demand so that no separate hot water tank for storing hot water therein is required. A dispenser is installed on the door for dispensing the hot and cold water supplied from the hot water tube and cold water tank to the outside of the refrigerator.