This paper studies Predictive Prefetching on a Web system that provides two levels of caching before information reaches the clients. We analyze prefetching on a Wide Area Network with the above mentioned characteristics. First, we provide a structured overview of predictive prefetching and show its wide applicability to various computer systems. The WAN that we refer to is the GRNET academic network in Greece. We rely on log files collected at the network’s Transparent cache (primary caching point), located at GRNET’s edge connection to the Internet. We present the parameters that are most important for prefetching on GRNET’s architecture and provide preliminary results of an experimental study, quantifying the benefits of prefetching on the WAN.