Unconfined compressive strength (UCS) of high plasticity clayey soil mixed with various amounts of cement and four dispersive agents was evaluated to investigate the effectiveness of the agents combined with the cement on the stabilization of the soil. A series of unconfined compression tests was conducted for the clay specimen mixed with 5 and 10 % of cement and four chemical agents such as sodium hexametaphosphate, aluminum sulfate, sodium carbonate, and sodium silicate with 0, 5, 10, and 20% of concentrations. The strength of the cement-soil mixture tends to mostly decrease when the mixture includes the agent. However, at low concentrations of aluminum sulfate (5%) and sodium carbonate (5% and 10%), the average UCS the soil-chemical agent-cement mixtures slightly increased compared to that of pure clay due to increasing the flocculation of the clay in the mixture. At high concentrations (20%) of all chemical agents, the UCS decreased considerably. With increase in cement content from 0 to 10% in the mixture, the degree of the UCS reduction remarkably increased. For 10% of cement, the UCS reduction is the highest for all soil mixtures containing chemical agent-cement, which is more than three times higher compared to that for the soil mixtures without cement.