Abstract. We describe a group membership protocol, called the timewheel group membership protocol, for a timed asynchronous distributed system. This protocol is a part of the timewheel group communication service that supports multiple group communication semantics simultaneously. The timewheel group membership protocol is unique in several respects. First, it has been designed for a timed asynchronous distributed system model. Second, it is optimized for those failure scenarios that are more likely to occur than others. In particular, it uses a very simple and fast algorithm to recover from single failures. Furthermore, the group communication service is not interrupted, if a failure suspicion turns out to be a false alarm. Third, this protocol incurs minimal processing load during failure-free periods. In fact, this protocol does not cause any extra messages to be exchanged during failure-free periods. Finally, as a consequence of using the timed asynchronous distributed system model...