Abstract. Building on research focusing on endogenous routine dynamics, we aim to understand how routines need to be brought together to achieve synergies in the post-acquisition integration processes. Based on a, longitudinal case study of a consultancy sector acquisition in France,, we apply a practice-based lens to study the intended combination of two existing routines and why its implementation turned out to be a failure. Our findings suggest that seemingly matching routines were not compatible in practice as the underlying patterns of action could not be easily combined. Our article sheds light on the role of routines in M&A and contributes to the literature by discussing a) the prevailing role of the interconnectedness of routines in effective acquisition integration and capability transfer and b) discrepancies between ostensive and performative aspects of routines as impediments to the implementation of the pre-acquisition plan in the post-acquisition phase. 11.Mirc, N., Seles, K., Angwin, D. N. (2017) When matching routines meet– a routine dynamic perspective on post-acquisition integration, Strategic Management Society Special Conference, San Jose, Costa Rica, December.