Key words: constitutive equations, strains, stress, elastic-plastic theories.rnAn associative constitutive model originally developed by C. S. Desai based on rateindependentrnelastoplasticity concepts is validated for the Red Clay Soils of Addis Ababa.rnThe basic concept of the model used herein was proposed and developed by Desairn(1980). The yield function is expressed in terms of the state of stress, while the evolutionrnor strain hardening process is characterized by using internal state variables such as thernirreversible strain.rnLaboratory tests are conducted to determine the material constants. The materialrnconstants that are associated with the model are found based on four different states of arnmaterial deformation process: the elastic, plastic accompanied by hardening, phasernchange from contraction to dilation and the ultimate state.rnThe model is then validated by comparing predictions with laboratory tests from whichrnthe constants were found, and also with tests not used for finding the constants.rnComparison of observed and predicted response show that the model yielded predictionsrnthat compared remarkably well with the observed behavior.