Diagnosis has been performed of the 1976/1977 and 1982/1983 El Niño events on the basis of NMC objective analyses. Evidence shows that in the prior period to the 1976/1977 occurrence, a weak winter monsoon dominated in east Asia in contrast to a strong monsoon for the 1982/1983 event; the intensity was responsible for the distribution and vigor of paired vortices around the equatorial western Pacific and hence of equatorial Pacific westerly anomalies. Moreover, anomalies of SST, OLR and velocity potential differ greatly between the events. In the light of our study, the 1976/1977 (1982/1983) El Niño is categorized as a weak eastern (robust western) event.