PME 32 and PME-NA XXX 2008 3 - 161 INSTITUTIONAL PRACTICES AND THE MATHEMATICAL IDENTITY OF UNDERGRADUATES Paul Hernandez-Martinez University of Manchester This paper reports on a study made at a Mexican university on the comparison between undergraduates from two different degrees, Applied Mathematics and Computer Science. The study focuses on the concept of (mathematical) identity, and seeks to investigate how this identity is mediated by the institutional cultures in which these students participate. The analysis of the data, obtained from questionnaires and interviews, shows that when students and lecturers engage in common practices within their institutions, they co-construct their identities and this in turn shapes the practices in which they participate. INTRODUCTION This paper is part of a study that aimed to explore how different undergraduate students build their mathematical identity and how this seems to be mediated by the institutional culture available to them. Here I report on the comparison of students undertaking undergraduate studies in Computer Sciences (CS) and Applied Mathematics (AM) at a Mexican university and how the academic activities in which these students participate seem to mediate their mathematical identities. The reason to choose these two groups of students for comparison obeys to the fact that both groups make substantial use of Mathematics during their undergraduate studies, but it was hypothesised that this subject takes different roles for each of them, and that this difference is influenced by the academic culture in which they develop as students. THEORETICAL FRAMEWORK Recent studies point out the importance that the academic context has on the success or failure of undergraduates in mathematics (Solomon, 2007; Brown, & Rodd, 2004) and in particular, to the great influence that institutional practices have in the development of these students’ understanding of specific mathematical concepts at university (Bingolbali & Monaghan, 2008). For example, in their study of Mathematicians and Mechanical Engineers, Bingolbali, & Monaghan (2004) use the concept of ‘positional identity’ (Holland et al, 1998) to explain how students position themselves differently as they participate in their respective departmental activities, and that this affiliation seems to influence their development of the concept of derivative. However, they acknowledge that their data is inconclusive about the dialectic nature of the relationship between identity and affiliation, and identity and knowledge development. In this paper, I will try to add to the existent literature by further exploring the nature of the relationship between (mathematical) identity and institutional practices. The notion of identity that I used here is informed by Cultural-Historical Activity Theory (CHAT). Within this framework, identity is conceived not as an individual process but one