In the Internet, proxy servers are tools that are used to facilitate clients for accessing websites and save network bandwidth. Basically, proxy servers uses cache to stored visited sites in order to deliver faster web accesses to users, without requesting to external target servers. With the limitation of cache size, however, a number of techniques have been proposed to potentially increase the performance of cache replacement methods. The objective of this study is to apply a data mining technique to generate frequent itemset patterns of the internet access by users. Data transactions are generated based on the allocated time slots of internet usage. As the public the Internet cluster, different users can use the same single computer; therefore, generating data transaction base on computer IP address is used by many users and may not extract the behavior of users. Association rules are generated using FP-growth algorithm. The frequent itemsets (rules) are then used to implement and extension of LRU cache-replacement technique. The experimental results show that the proposed technique provides promising result and is superior to the base-line cache replacement techniques (i.e. FIFO and LRU).