This study explores identity negotiation through talk-in-interaction by undergraduate female students at a male dominated study program of Computer and Systems Sciences at Stockholm University. The main aim of this study is to investigate what interactional identities are occupied by the female students in relation to Membership Categorisation Device “Gender”. Theoretical framework that has been developed and used in this study is a combination of Grounded Theory and Membership Categorisation Analysis which is a part of Conversation Analysis developed by Harvey Sacks. The data has been collected through ten semi-structured interviews that have been conducted with undergraduate female students of Computer and Systems Sciences at Stockholm University. The results demonstrate that there are various ways in which the female students negotiate their interactional identity in relation to Membership Categorisation Device “Gender”. The use of Membership Categorisation Device “Gender” is both appropriated and rejected in negotiation of interactional identity. The results of this study might be useful in providing a better understanding of how interactional identity is negotiated by undergraduate female students of Computer and Systems Sciences at Stockholm University. In turn, that might facilitate effort of making gender ratio in male dominated IT-areas more equal. Moreover, the results of this study may contribute to further research on the relationship between gender identity negotiation by women in male dominated IT-areas and the phenomenon of “Gender Paradox”