The experimental findings on the mechanical behavior of clays with dispersed microfabric are indicative of the need for comprehensive evaluation of the constitutive theories being widely used in practice. The clay deposits can be found having all the stages of microfabrics in their natural state and the dispersed microfabric is one of those. Despite the fact that the effects of microfabric can be radical sometimes, those are seldom given due consideration during the design process. Since the success of numerical modelling of a geotechnical structure is strongly dependent on the accuracy of the constitutive equations, the results produced by commonly used constitutive models can be highly misleading. The present paper is focused on identifying such issues which make the study of dispersed clays important and show the need for incorporating the influence of microfabric into constitutive formulations. Two of the most widely known models, Modified Cam-Clay (MCC) model (Roscoe and Burland, 1968) and the single hardening (SH) model (Lade, 1990), have been calibrated for the Kaolin clay with dispersed microfabric and the predicted response has been compared with the experimental observations. This comparative study has been used to provide an insight into the important issues which still need attention.