Time synchronization is an important aspect of distributed computer systems and networks. Nodes must be synchronized to a common clock to determine slot durations for a TDMA based transmission scheme. Most efficient slot-assignment algorithms apportion the TDMA slots with the underlying assumption of a reasonably accurate global synchronization of the network. In this paper, we propose a novel synchronization protocol for ad hoc, sensor, and other dense multi-hop infrastructure-less wireless networks. The protocol performs a random leader election to achieve global network synchronization. We have analyzed the variation of synchronization time and error with different node densities and mobility speeds, by simulating the protocol. Expressions have been derived reflecting the worst case synchronization error, and the maximum synchronization time, for a network with uniform distribution of nodes. Simulation results show that out-of-band and piggybacked signaling have good accuracy of synchronization, and that a considerable bandwidth saving occurs with piggybacking on data or acknowledgment packets. © Springer-Verlag Berlin Heidelberg 2005.