In cooporation with the Oklahoma Department of Transportation and the Federal Highway Administration, U.S. Department of Transportation, a research project was undertaken on June 1, 1973, by the University of Oklahoma to study the stabilization of Oklahoma shales. Inasmuch as shales had already been studied, identified, classified and characterized in a previous study (1972), the main objective of the present investigation was to determine the type and amounts of stabilizing agents to yield optimum conditions in upgrading the shales for highway construction purposes. Eight Oklahoma shales representing regional characteristics but differing texturally and mineralogically were selected on the basis of the 1972 study. Of the various stabilizing agents used, it was found that 6 percent hydrated lime, 14 percent portland cement, and 25 percent flyash give imptimum conditions by imparting acceptable strength levels to the shales. The degree of strength attained varies inversely with the plasticity of shale. On the basis of compressive strength, cyclic loading, and weatherability criteria, cement is the most effective additive, flyash the least and lime moderately effective. Combinations of the three stabilizing agents show that shales can be upgraded strength-wise when the three main stabilizing agents are used conjunctively; in fact, the data suggest that such uses are more economical and mor promising. The addition of small amounts (less than 2 percent) of NaC1, CaC1 2, NaOH, and Na2CO3 to the shales which already have been mixed with one of the main stabilizing agents, further enhances the stabilization benefication.