In the context of climate change, knowledge and studies on precipitation in the Amazon Basin (AB) are determinant for environmental aspects such as hydrology, ecology, as well as for social aspects like agriculture, food security, or health issues. Rainfall data availability with a wide geographical coverage and a good resolution is thus crucial for these purposes. Remote sensing techniques can provide an alternative to ground-based rainfall data but it is imperative to assess the quality of these estimated data. Hence, this paper aims to describe the reliability of the Topical Rainfall Measurement Mission (TRMM) 3B42 Version 7 (V7) Real Time (RT) at daily scale over the Amazon Basin (AB). The study covers the period of March 2000 to July 2013. TRMM estimates were compared with observations from 205 quality-controlled rain gauges stations. First, the spatial distribution of mean daily rainfall across the whole AB was validated using quantitative (Bias, Relative RMSE) and categorical statistics (POD, FAR). Estimations are more accurate in the lowlands than in the highlands. Furthermore a contrast of quality in estimates within the Andean regions can be noted. Second, TRMM 3B42 V7 RT succeeds in replicating regional rainfall regimes across the AB. The Andean regions show the worse results. However neither relevant relationships nor correlations appear with the altitude. However, the location of a rain gauge and its exposure seem to be relevant explanations of overestimations by TRMM 3B42 V7 RT in these mountainous regions.