This study investigates the impact of monthly Ganges–Brahmaputra river discharge variations on Bay of Bengal salinity and temperature during the period 1992–1999. The Ganges–Brahmaputra river discharge is characterized by a well-defined seasonal cycle with strong interannual variations. The highest/lowest yearly peak discharge occurs in summer 1998/summer 1992, with 1998 value amounting to twice that of 1992. This river discharge is then used to force an ocean general circulation model. Our main result is that the impact of these rivers on the variability of Bay of Bengal sea surface salinity is strong in the northern part, with excess run-off forcing fresh anomalies, and vice versa. Most of the years, the influence of the interannual variability of river discharge on the Bay salinity does not extend south of ∼10 ◦ N. This stands in contrast with the available observations and is probably linked to the relatively coarse resolution of our model.