Abstract: This paper uses trace-driven simulations to evaluate the performance of different cache management techniques for multi-level Web proxy caching hierarchies. In particular, the experiments consider heterogeneous cache replacement policies within a two-level caching hierarchy, and size-based partitioning across the levels of a caching hierarchy. Three different synthetic Web proxy workloads are used in the study, reflecting complete overlap, partial overlap, and no overlap in the workloads seen by the child-level proxies. The simulation results demonstrate that heterogeneous replacement policies and size-based partitioning each offer modest improvements in caching performance. The sensitivity of the results to the degree of workload overlap is also discussed.