In the austral winter of 1993, during a COROAS hydrographic cruise in the South Brazil Bight (SBB), an unexpected mass of cold and fresh water was observed on the continental shelf near 23 ¿S. Subsequent analyses of different data sets suggested that the origin of that water was probably the Argentine continental shelf, near the Rio de la Plata mouth. In this article, a 13-year time series of AVHRR Sea Surface Temperature anomalies is analyzed to investigate the occurrence of this phenomenon in other periods. The results of these analyses and a good correlation with the Southern Oscillation Index suggest that the penetration of these waters into the SBB occurs in a frequency that may be associated with ENSO events. ¿ 1999 American Geophysical Union