This research aims at identifying the religious behavior changes of the former residents of UNIRES Putri UMY after receiving guidance during their stay at UNIRES UMY. This research used qualitative approach located at UNIRES Muhammadiyah University of Yogyakarta. The subject of this research is the former residents of UNIRES Putri UMY who had received minimum 1 academic year of guidance. The data were compiled through observation, interview, and documentation. The data were then analyzed. The results of this research are: (1) the students of the former residents of UNIRES Putri UMY are experiencing religious behavior changes such as the decreasing religious activity. When they were still staying in UNIRES, these students were often and were used to perform some religious activities such as congregational prayers, reciting Qur’an after prayer, or wearing Shari dresses. However, after leaving UNIRES Putri UMY, those religious activities are rarely done. (2) these religious behavior changes among former residents of UNIRES Putri UMY is influenced by the new environment which is totally different from that in UNIRES Putri and also by new cultures outside the scope of Muhammadiyah University of Yogyakarta. Those two factors are the background for the religious behavior changes that intrigue the former residents of UNIRES Putri UMY to neglect some religious activities such as congregational prayer, Sunnah prayer, reciting Qur’an after prayer, and wearing Shari dresses. The absence of prohibition and regulation is the main factor that causes the religious behavior changes among former residents of UNIRES Putri UMY.