The deployment of large-scale wireless sensor networks (WSNs) presents various challenges whose solution requires the design and development of power-and-time efficient protocols. In this context many proposals and various standards have suggested the use of time division multiple access (TDMA) in order to guarantee tight-time scheduling and high overall network throughput under high load conditions. However, in TDMA networks the time and overhead required during the setup phase are major drawbacks that are often overlooked. In this paper we introduce a simple and robust algorithm specially tailored to be used during the setup phase of a TDMA-based WSN. The proposed algorithm makes use of 2C, a conflict resolution protocol with some advantageous properties. As a case study, we consider the setup phase of the synchronous protocol SA-MAC. Our results show that the proposed algorithm is able to configure highly populated networks in significantly shorter times than traditional CSMA/CA. Furthermore, an experimental prototype has been developed allowing us to show the feasibility of deploying the proposal using off-the-shelf components. Copyright © 2010 Fernando Royo et al.