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A dispersed soil has been artificially prepared by adding Na2CO3 to natural clay in different proportions. • The proportions are as follows 5%, 15%, 25%, 30%, 35%, and 40% by weight. • The target of this investigation is to investigate the effect of degree of dispersion of the soil on Atterberg limits. • The study showed that the percentage of dispersion increases with Atterberg's limits Dispersive soils are characterized by three features: (1) unstable structure, (2) they are readily flocculate in water, and (3) very erodible. The use of dispersed clay soils in hydraulic structures, dams and road dams can cause serious engineering problems when this soil is not identified and used befittingly. There is a simple way to determine soil dispersion and more difficult to measure dispersion. (Atterberg'slimits) (grain size analysis), and (visible classification) are not enough to recognize between (normal clays) and (dispersive clays).ASTM tests can identify dispersive clay, these include: (double hydrometer test), (chemical tests), (Crumb test), and (Pinhole test). In this paper, the dispersed soil has been artificially prepared by adding Na2CO3 to natural clay in different proportions.The proportions are 5%, 15%, 25%, 30%, 35%, and 40% by weight. The target of this investigation is to investigate the effect of degree of dispersion of the soil on Atterberg limits. The study showed that the percentage of dispersion increases with Atterberg'slimits and the dispersion ratio and the plasticity index relationship are related by a direct relationship.