This paper presents mobile robot localization using coded infrared light as artificial landmarks. Different from RFID, identification using infrared light has highly deterministic characteristics. IRID(InfraRed Identification) is implemented with IR LEDs and photo transistors. By putting several infrared LEDs on the ceiling, the floor is divided into several sectors and each sector is set to have a unique identification. The coded infrared light tells which sector the robot is in, but the size of the uncertainty is still too large if the sector size is large, which usually occur. Dead-reckoning provides the estimated robot configuration but the error is getting accumulated as the robot travels. This paper presents an algorithm which fuses both the encoder and the IRID information so that the size of the uncertainty becomes smaller. It also introduces a framework which can be used with other types of the artificial landmarks. The characteristics of the developed IRID and the proposed algorithm are verified from the experiments.