The objective of this work was to determine if mung-bean, peanut and soybean respond to rhizobial inoculation under rainfed upland conditions in Cambodia and to compare the response to inoculation with application of a nitrogenous fertiliser. The effect of rhizobial inoculation and fertiliser nitrogen on nodulation and yield of mungbean, peanut and soybean under rainfed upland conditions was studied in a series of 28 experiments in 2004, 2005, and 2006 in the provinces of Kampong Cham and Battambang, Cambodia. Sites were selected on the two main soil groups used for upland crop production: Kompong Siem (vertosol) and Labansiek (ferrosol). Commercial inoculum containing 'Bradyrhizobium' strains specific to the three crops was obtained from Australia. The experiments were of factorial design with two levels of inoculum (nil, plus) and three levels of nitrogen as Urea (0. 40 and 80 kg N/ha) in a split-plot design with three replicates.