This publication considers radionuclide transfer in tropical and arid environments with a focus on root uptake by crops from soils. The data collected and analysed are relevant for estimating the transfer of radionuclides through food chains to humans and for assessing radiation doses to the public due to intakes of these radionuclides in plant products used as food. The data relate to equilibrium conditions between the radionuclide’s dynamics into and out of the compartments of the environment and are appropriate for radiological environmental impact assessment in planned and existing exposure situations where such conditions have been established. Moreover, this publication classifies the data according to an international climate classification scheme and compares the summary values derived for tropical and arid environments with those presented in IAEA Technical Reports Series No. 472 for temperate environments.