Sea surface temperature (SST) variabilities on time scales of 10--14 years have been documented in various parts of the Atlantic Ocean. Here we present observational evidence that these regional variabilities are part of a coherent pan-Atlantic decadal oscillation (PADO) characterized by zonal bands of SST and wind anomalies stacked in the meridional direction with alternate polarities from the South Atlantic all the way to Greenland. We propose that the interaction of wind, evaporation and SST is key to establishing this interhemispherical PADO, based on results from a new ocean-atmosphere coupling model. Forced by extratropical wind forcing, the model successfully reproduces the observed decadal oscillation in both SST and wind velocity over the Tropics. This decadal extratropical forcing of the Tropics is in sharp contrast to the well-known Tropics-to-extratropics teleconnection that operates on interannual time scales in association with El Nino/Southern Oscillation (ENSO). ¿ 1998 American Geophysical Union