One challenge for conversation analytic research on identity is to demonstrate that and how identities are made relevant and consequential for the participants of an interaction. Drawing on Harvey Sacks's work on membership categorization and conversation analytic methods, the aim of this paper is to explore the 'reflexive codetermination' (Schegloff, 2007a) of membership and social action-how participants make sense of particular actions through an orientation to locally relevant membership categories, and how category membership is invoked in the enactment of particular social actions. Using video-recordings of a meal shared by a young child, his parents, and his grandparents, the paper examines how identities are made operative in and through the moment-by-moment organization of specific sequences of action. The analysis examines how participants oriented to membership within stage-of-life and family categories, and as guests and hosts, and shows how the relevance of these memberships was enacted through, and consequential for, phenomena such as turn design, turn-taking organization and embodied action. In demonstrating how the relevance and consequentiality of a particular identity can shift over the course of a sequence the paper engages with analytic problems involved in research on identity-particularly with respect to the operation of social structural identities (such as child) when contextually bound identities (such as guest) are also potentially relevant and consequential. © 2010 Elsevier B.V.