The La-Niña phenomenon, anomalous cooling of superfícial waters in the Pacific ocean Equatorial Central office, starts to characterize itself in middle of one year, reaches its maximum intensity in the end of that year and is wasted in middle of the following year. During 1998-2000 the La-Niña event, the climatológica average was registered positive an average anomaly in the region of approximately 50,0 mm in relation. The station located in the city of Juruti, was registered the biggest positive precipitation anomaly during the 1998-2000 event, in the order of approximately 170,0 mm. The normalized average shunting line for the region was of approximately 4,0 being that the stations of Juruti and Curuai, had registered biggest positive shunting lines, approximately 9.0. The shunting line standard for the region during the La-Niña of 1998-2000 was of approximately 17.5. This work has as intention to show in a general way, that type of performance the La-Niña Phenomenon of 1998-2000 intervened with the precipitation regime of the Region of the Amazon Medium.