We study freshwater discharge from the Amazon River into the tropical Atlantic using monthly mean multi-sensor data from September 1997 to July 2003. In order to demonstrate freshwater discharge, we used chlorophyll concentration (Chl_a) and diffuse attenuation coefficient (DAC) measured by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and salt steric height anomaly (Δη'S) derived from Integrated Multi-Sensor Data Analysis (IMSDA). IMSDA was obtained from estimating the long term-time series of Δη'S by removing the thermal steric height anomaly (η'T) from altimetry data. Comparisons of long-term time series of Δη'S, Chl_a, and DAC were made with mooring data at 8¿N, 38¿W, which were highly correlated. There are three- to five-month lags between the Amazon River discharge and 4¿N latitude estimated from latitude-time diagram derived from SeaWiFS measurements.