Resumen
This study examined the ENSO and Rain Anomaly Index in Mato Grosso do Sul state using rainfall data from 32 sites obtained from the National Water Agency through its web platform (www.hidroweb.ana.gov.br). Annual totals were compared with ENSO occurrence information at http://www.cpc.ncep.noaa.gov. Precipitation anomaly indices (ACI) were generated to qualitatively evaluate the series with ENSO. The years considered in El Niño were classified as extremely wet by the IAC. La Niña's effect was confirmed by the IAC as extremely dry years. Comparing the IAC obtained from the NOAA website information there is a good correspondence between the years under the action of the positive component of ENSO.