In this paper, we propose a novel cache management strategy that uses the notion of "overload" where overload is defined as a situation when there is insufficient proxy cache for a new incoming user in a mobile region. In an overloaded situation, there will be increased network traffic (since the original server will need to be contacted) and increased service delays for mobile hosts (due to cache misses). The proposed techniques attempt to decrease the penalty of overloaded traffic and to reduce the number of remote accesses by increasing cache hit ratio. Our cache replacement algorithm is holistic in that it considers (i) mobility of the clients, (ii) predicted overloads, (iii) sizes of cached objects and (iv) their access frequencies in determining which object's cache (how much cache space) to be replaced, and when to replace. Performance results show that our overload-driven cache management strategy outperforms the existing popular policies.