ABSTRACT Cultural identity reinforcement is an individual identity in understanding cultural background and maintaining and strengthening culture inherited to the individual by certain cultural identity reinforcement steps. Cultural identity reinforcement is conducted to inform exclusive side of a culture. Cultural identity is indirectly shaped and needs willingness of each individual to reinforce their cultural identity. One of steps to reinforce cultural identity is by performing ingroup and out-group communication. Arabian ethnical group in Surakarta performs in-group and out-group communication to indicate that their ethnic is minority ethnic group that tries to maintain their Arabian generation ethnicity and keep their cultures which can strengthen their ethnic generation cultural identity. This research depicts how in-group and out-group communication are performed as an effort to reinforce cultural identity. One of result obtained is factor in strongest in-group and out-group communication in performing cultural identity reinforcement. This research utilizes ethnical ethnography in order to focus on review object and explain objects around it. Also, this research uses interview method, direct observation and document investigation in the data collection process. Keywords: cultural identity reinforcement, Arabian ethnic group generation in Surakarta, in-group communication, out-group communication.