Abstract. Distributed transactional systems require an atomic commitment protocol to preserve atomicity of the ACID properties. However, the industry leading standard, 2PC, is slow and adds a significant overhead to transaction processing. In this paper, a new atomic commitment protocol for main-memory primarybackup systems, C2PC, is proposed. It exploits replication to avoid disk-logging and performs the commit processing in a circular fashion. The analysis shows that C2PC has the same delay as 1PC, and reduces the total overhead compared to 2PC.