It has been widely proposed that student voices should play a crucial role in designing and implementing curriculum and instruction that promote students' engagement in science learning. In this study we examined the voices of two seventh grade boys from a low-income urban community as they worked together in an after-school program to create a student-directed video documentary about science. Our analysis showed that these students used their voices to construct identities that they cared about in school, by reconstructing some aspects of their school identity that did not match who they aspired to be, as well as by gaining new resources to enact their desired identities. The examples provided demonstrate that integrating student voice in a science project can make participation in science a valuable tool in students' identity formation. © 2006 Wiley Periodicals, Inc. J Res Sci Teach 43: 667–694, 2006