Interband cascade laser arrays with continuous-wave (CW) watt-level output power at room temperature are demonstrated. A three-emitter laser array episide-down bonded on a diamond submount exhibited a CW output power in excess of 1 W at 10℃. The wall-plug efficiency of the laser array is almost the same as that of a single emitter, indicating that there is little heat accumulation caused by the thermal interference between the emitters in the array structure.