High-resolution climatic and hydrological observations and results from a land surface / terrestrial ecosystem model, linked to a regional-scale river-routing algorithm are used to document the links between the El Niño - Southern Oscillation (ENSO) phenomenon and anomalies in climate, surface water balance and river hydrology within the Mississippi Basin and its major sub-basins. ENSO is mainly associated with positive winter temperature anomalies in the Mississippi, although there are regions of significant change throughout the year. Precipitation patterns alternate between positive and negative anomalies depending on season and location. The regional climate anomalies associated with El Niño mainly influence ET in the western portion of the basin, and total runoff in the eastern half. The opposing signs of total runoff anomalies in the Upper Mississippi and Ohio nearly cancel and result in negligible change to streamflow at the Mississippi basin outlet in Vicksburg. El Niño is also associated with decreased November - April snow depth throughout most of the basin. La Niña is linked to negative ET anomalies in the central portion of the basin in summer and fall, and positive total runoff anomalies during most of the year in the southern tier. The resulting positive anomalies of streamflow act to increase winter streamflow at Vicksburg. La Niña is also associated with increased snow depth in the northern Upper Mississippi and northern Missouri. Other climatic patterns may be more strongly correlated with hydroclimatic anomalies in the Mississippi. Further analysis of these teleconnections may be possible with the IBIS-HYDRA modeling system to better understand linkages in the physical system.