Recently, social concerns about addiction problems not only to substances like alcohol and drug but also to gambling or internet have been increasing. Addiction is caused by a combined influence of biological, psychological. and social factors. However, addiction may also occur due to weak will-power or poor education on addiction. Even though addicted behavior provides temporal mood change such as euphoria, satisfaction. or relaxation. it leads to serious physical and mental disorder of the addicted person and its family members, which possibly results in fatal consequences. Nurses are in an environment to meet and take care of those who are addicted or vulnerable to addiction in order to help the clients to recover or to prevent people from addiction. Despite the importance of nurses role in addiction problems, there is a lack of consistency of addiction is often interchangeably used with other similar concepts in the society. In this study, a concept analysis of addiction was performed to more clearly and comprehensively understand addiction and to develop effective nursing intervention methods for addicted clients. The analysis is conducted according to a series of processes described by Walker and Avant. The defining attributes of addiction identified in this study are as follows: 1) existence of object 2) control loss 3) withdrawal symptoms 4) continued use despite adverse consequences.