Time and cost are the two most important constraints among the four project constraints which are time,cost,quality and safety in project management. In this desertation I have addressed two of the above constraints and it is very interesting issues for project stakeholders in construction and other projects. This desertation has shown the relation ship between time and cost and a model is developed to predict construction time knowing project cost.Further more,this work has shown that there is a direct relationship between Construction cost and building total floor area and a model is develped to predict cost knowing the total floor area of the building from preliminary design. The desertaion can be used as asource document for further study.Similarly the desertation has reviewed different publications which are written in the area.