Hydrodynamic modelling of Amazonian rivers is still a difficult task. Access difficulties reduce the possibilities to acquire sufficient good data for the model calibration and validation. Current satellite radar technology allows measuring the altitude of water levels throughout the Amazon basin. In this study, we explore the potential usefulness of these data for hydrodynamic modelling of the Amazon and Napo Rivers in Peru. Simulations with a 1-D hydrodynamic model show that radar altimetry can constrain properly the calibration and the validation of the model if the river width is larger than 2500 m. However, sensitivity test of the model show that information about geometry of the river channel and about the water velocity are more relevant for hydrodynamic modelling. These two types of data that are still not easily available in the Amazon context. © 2012 Elsevier Ltd.