In Order to increase the quality of project implementation much research will need to be carried out in Indonesia and abroad. In 1982 The Business Roundtable's team in the US found that opportunities to reduce project costs and schedules by using existing and new construction technology are lost because construction too often is relegated to operate as a produstion function separated from financial planning, scheduling, and engineering or architectural design. The Construction Industry Institute's (CIT) Task Force defines this term as Constructability, which is the optimum integration of construction knowledge and experience in planning, engineering, proqurement, and field operations to achieve overall project objectives. As the customer, the owner gets what he insist on. As the leader of the project team, the owners plays a vital role in using constructability to meet project objectives. Specific project documenting the constructability effort have shown that owners accrued an average reduction in total project cost of 4.3% and in project schedule of 7.5%. These savings represented a 10- to-1 return on the owner's investment in constructability. Altough significant saving can result, the opportunities available are often overlooked by owners. This research was conducted to study the role of project owners for implementing constructability improvement during conceptual planning phase which leads to an improven project time performance of construction project in Jabotabek Area. A questionnare survey was used as the method for collecting data. Statistical analysis was performed to analyse the data and to develop a regression model between the role of project owners for constructability improvement during conceptual planning pQase and the performance of construction project's schedule. The result of this study shows a positive tinier correlation between the project owner's role for constructability improvement during conceptual planning phase and the project time performance. The main variables are assuring that key individual assigned to the project team each have appropriate experience with the project and clearly state the priority of the project objectives.