Thanks to the ORE HYBAM project, hydrological, suspended sediment, geochemical and physico-chemical data can be acquired at daily, ten-day and monthly time steps at about fifteen gauging stations, mainly on the larger rivers of the Amazon basin. The aim of this network is to investigate the piedmont areas, the flood plain tributaries, the tributaries that originate in the Andes and those that are draining the Brazilian and Guiana shields. The ORE HYBAM network, operated by research institutions and national agencies, is interested in the mass transfer within the Amazon basin and towards the Atlantic Ocean, in its sensitivity to climatic variability and anthropogenic activities, and in the key role of wetlands for mass transfer. These data, acquired with standardized collection and analysis methods, are also important for determining the global balance. They are freely available via the Internet (http://www.ore-hybam.org) in the form of graphics, and can be downloaded in ASCII files. Copyright © 2006 IAHS Press.