<p>The study of precipitation and streamflow trends is important for understanding hydrological variability and determining what has influenced increases or decreases. This paper analyzes the trends in the annual, spatial–temporal, series of rainfall (annual rainfall totals and maximum annual rainfall) and streamflow (annual mean, annual maximum and annual minimum) in the Amazon River Basin in the Brazilian portion using the Mann–Kendall and Sen's Slope non-parametric tests for five different periods (1975–2014, 1980–2014, 1985–2014, 1995–2014, 2000–2014). The results show that the mean streamflow series is increasing in the Amazon Basin for all the periods analyzed. In the sub-basins on the right margin of the Amazon River, Tapajos and Madeira Rivers, the most recent period (2000–2014) shows the greatest upward trends in the average annual streamflow, an area with greater land use and occupation. In the analysis of maximum streamflows, the Óbidos gauging station had an increasing rate of growth for flood events. As for rainfall, there are significant upward and downward trends in several different regions of the basin. A comparison of the magnitude of the trends using the Sen's Slope test shows that there is an upward trend in streamflow rates throughout the Amazon basin, and as for rainfall, there are areas of increase and decrease, i.e. precipitation is not the only variable that influences streamflow in the Amazon River basin. However, it is necessary to study and apply more robust methodologies to assess whether anthropogenic variables and climatic variables influence the hydrological cycle.</p>