—Uplink-Downlink imbalance is a characteristic of all wireless networks which greatly impacts system performance, and must be accounted for in system design and simulation. However this property seems to have received sparse attention in literature. This paper describes imbalance, its potential sources, and its impact on traffic and overhead channel performance, soft handoff, adaptive server selection, and sector load control schemes. This paper defines imbalance metrics, a model for simulating antenna imbalance, and presents simulation study of system robustness to link imbalance using cdma2000 1xEV-DO as an example.