Interdependence between El-Nino/Southern Oscillation and Indian monsoon is analyzed with the use of Granger causality estimation from data for the period 1871-2006. Four different versions of the Nino-3 and Nino-3.4 index are used to check robustness of the results. We reveal a non-symmetric bidirectional and even alternating character of coupling that extends previous knowledge about the presence of negative correlation and intervals of phase synchrony between the processes. Citation: Mokhov, I. I., D. A. Smirnov, P. I. Nakonechny, S. S. Kozlenko, E. P. Seleznev, and J. Kurths (2011), Alternating mutual influence of El-Nino/Southern Oscillation and Indian monsoon, Geophys. Res. Lett., 38, L00F04, doi:10.1029/2010GL045932.