Monitoring cyanobacteria blooms in inland waters is largely restricted to in situ water samples. An alternative for quick access to algae blooms is the use of satellite images. However, the identification of the species mapped on the images is still dependent on microscopy techniques. Therefore, as an attempt to develop techniques of cyanobacteria monitoring, this research had two objectives: 1) Map the spatial-temporal distribution of cyanobacteria bloom in the Tapajós River using multi-satellite approach (MERIS/Envisat, Landsat, e Rapideye); and 2) Evaluate the use of Particle Size Distribution (PSD) to estimate biovolume (µl/l) of three different cyanobacteria with different sizes and shapes (Microcystis sp., Anabaena variabilis, e Synechocystis sp.,). This research mapped cyanobacteria blooms for the past 10 years which seems to be one of the largest blloms in Brazilian inland waters. The multi-satellite approach showed promissing results for a time-series analysis. The biovolume estimated by LISST (optical sensor) showed satisfactory correlation to biovolume observed on microscopy, which indicates this approach as a quick but generic approach for sepcies dominance. For a proper use of LISST for biovolume estimation, one has to consider the presence of non-algal particles, and its limiation on biovolume estimation under high cells concentration.