Since the first laser device Ruby laser was created in 1960s, lasers have been introduced to the management of soft tissue. The erbium-doped yttrium aluminium garnet (Er:YAG) laser was approved for the hard tissue management in dentistry by Food and Drug Administration in 1997. Recently, it has demonstrated for the effective elimination of soft and hard tissue with minimal damage and even or faster wound healing. In addition, the irradiation with Er:YAG laser has a bactericidal effect which can be used to sterilize gingival pocket with low thermal damage and be effective for the maintenance of dental implant. This review reveals the basic character of high absorption coefficients of water and the clinical dental management of Er:YAG laser.