In this paper, a multiagent-based voltage and reactive power control in the case of a multiple contingency is presented. Incorporating the agent-based autonomous feature to the intelligence of the remote terminal units, the present power system control structure can be used to help in preventing system voltage collapse during catastrophic disturbances. The control algorithm is based on a decentralized architecture of intelligent agents and the determination of a local zone that can carry out quick countermeasures in a decentralized manner as a multiagent system (MAS) during an emergency situation. An adaptive determination of the local zones undergoing voltage collapse has been developed based on the electrical distances among the generators and loads. Once assigned, the elements of the Jacobian matrix can be used to determine the optimum actions that need to be carried out at each power system element (such as increasing the voltages of generators and load shedding) within the assigned local zone. The contract net protocol is used for agent interactions. Simulation results using the IEEE-57 bus system show that the proposed method can act quickly to respond to emergency conditions to ensure that voltage collapse can be avoided.