Embodiments of the present invention provide a refrigerator, comprising a main body having a food storage compartment therein, a door installed on the main body and having an ice compartment therein and for opening and closing the food storage compartment, a compressor, a condenser, and an expansion valve that are installed in the door, an ice maker installed in the ice compartment, the ice maker comprising a tray configured to receive and contain water therein, and a refrigerant pipe line coupling the compressor, the condenser, and the expansion valve to each other and configured to cool the tray by conduction, and wherein the ice maker further comprises a heater disposed on a perimeter of the tray and a drain duct disposed below the tray and configured to collect defrost water, and wherein a portion of the heater extends into the drain duct.