In multi-network environments, Vertical Handoff decision plays an important role. The decision on which network to use, becomes much more complicated, because both the number of networks and the decision criteria increase. Hence, an intelligent handoff decision algorithm is very important for heterogeneous network access. This paper presents an optimized vertical handoff decision algorithm based on mobility prediction. Since the wireless networks support high speed mobility, frequent handoffs occur. Mobility prediction plays an important role in the efficient operation of wireless networks without handoff interruption. This algorithm uses Hidden Markov Model (HMM) predictor that can accurately estimate the next location visited by a Mobile Node (MN), given current and historical movement information.