We are successful in simulating the recently discovered ocean-atmosphere coupled phenomenon called the Indian Ocean Dipole for the first time, using a coupled general circulation model without flux correction. During the analyzed 50 years of model integration, the anomalous climate events have appeared 8 times over the Indian Ocean (IO). They are characterized by the cooling of the sea surface temperature (SST) in the southeastern tropical IO and the warming of the SST in the western tropical IO, associated with the anomalous easterly winds along the equator. The spatial pattern of the anomalous SST shows an east-west dipole mode (DM) structure that is similar to the recent reports. The simulated DM events are independent of the El Ni¿o simulated in the same model. The heat budget analysis shows that the tropical air-sea interaction, which is strongly influenced by ocean dynamics, is crucial in generating the model DM events. ¿ 2000 American Geophysical Union