Maize crops grown during the summer rainy season in the tropics occasionally face extreme weather conditions that limit crop establishment and yield potential. Among various abiotic stresses, contingent/intermittent soil waterlogging is one of the important constraints for maize production in the Asian tropics and many other maize growing areas around the world. Rainfed maize crops grown during the monsoon season in the Asian tropics occasionally face temporarily waterlogged soils and anaerobic conditions, even in well drained fields. These waterlogged soils adversely affect various crop growth stages, overall plant stand and final grain yield. Moreover, the increasing demand for maize in Asia is rapidly transforming cropping systems in the region from rice monoculture to more profitable rice-maize systems. However, maize production in rice-maize systems frequently faces the problem of early stage excessive soil moisture, as the soils of paddy fields are often saturated due to late monsoon rains. This manual was developed for maize breeders and field technicians who manage screening/phenotyping for waterlogging tolerance with the purpose of identifying genotypic variability in maize for use in breeding programs targeting waterlogging tolerant maize.iv, 24 pages