Construction of building over high clay content soil is unsafe because the soil will shrink during the dry season and swell during the rainy season. During shrinkage of soil, differential settlement of foundation will occur and during swelling of soil, an uplift ing force will act overbuilding. These will lead to the collapse of buildings and causes cracks in buildings. Addition of stabilizers to increase the index and engineering properties of soil will be economical when compared with other methods. By add ing conventional stabilizers like lime, fly ash, rice husk, etc., to the soil, the properties will get increased. Same results were obtained when an eco-friendly, non-toxic, bio-en zy me called „Ter ra zy me? is  added to the s oil. In this  project, we are comparing the compressive strength of terrazyme treated soil sample with that of soil sample treated with both terrazyme and fly ash. The unconfined compressive strength of sample treated with both terrazyme and fly ash is appreciable when compared with the sample treated only with terrazyme. The compressive strength increases by increasing the curing period of samples. Thus, the addition of both fly ash and terrazyme to the sample will give appreciable results in soil properties when compared with terrazyme only t reated samples. Keywords:Clayey soil, unsafe, terrazyme, fly ash, combined