We present a prefix forwarding algorithm for content-based publish/subscribe systems. Our algorithm performs only one content-based match per message regardless of the number of routers (hops) traversed from the source to the destination. Moreover, prefix forwarding preserves the decoupling properties of publish/subscribe system. Prefix forwarding does not put any restriction on the content of the messages. The presented algorithm does not introduce any false negatives and allows to tune the false positive rate to balance the bandwidth and processing overheads. We provide experimental results confirming the properties of the proposed approach. Categories and Subject Descriptors C.2.4 [Computer-Communication Networks]: Distributed