In this talk, I will discuss observed patterns of decadal climate fluctuations over the tropical Indo-Pacific Ocean since the middle of the 19th century using a variety of data sets and simple analysis techniques, following in the spirit of Gene Rasmusson's classic ENSO studies. The results show that classic ENSO indices such as the “Nino3.4 SST Index” and the “Darwin-minus-Tahiti Southern Oscillation Index” are not optimal for characterizing the decadal variability, and that the Indian Ocean plays a more prominent role in decadal variability than interannual ENSO variability.