The correlation between Indian Ocean sea surface temperature and Niņo-3 sea surface temperature is used to estimate the relation between tropical Indian Ocean and Niņo-3 and consequently the effect of east Pacific SST variability on Indian Ocean SST variability. The COADS dataset from January 1945 to December 1989 are analyzed on a 1° by 1° global grid. The data were smoothed using a 5-month running mean filter prior to the analysis. Correlation analyses were carried out up to lag/lead of 12 months. Significant correlation is obtained for the whole Indian Ocean, except the south eastern corner. Maximum correlation is observed south of Sri Lanka when Indian Ocean SST lags Niņo-3 SST by 4 months. The SST anomalies in the tropical ocean were found to force SST anomalies of the same sign in the Indian Ocean. In turn, there was no evidence that the Indian Ocean can significantly affect the ENSO cycle. The Indian Ocean is covered with anomalous SSTs of the same sign 4 months after large scale SST anomalies are observed in the east equatorial Pacific. The findings here explicate that the ENSO signal is passed on to the Indian Ocean through an atmospheric circulation change, forced by east equatorial Pacific anomalies, which in turn affects the heat flux into the Indian Ocean.