Heat exchanger networks (HENs) play a significant role in the energy conservation of any process industry. The HENs are used to maximize heat recovery by exchanging heat between hot and cold process streams. Therefore, the optimum design of HENs is extremely important to reach the maximum efficiency of energy systems. Many graphical methods have been develope d during the last four decades for synthesizing of heat exchanger networks (HENs). However, most of these methods have only been evaluated for retrofitting design of HENs. In the grassroots design situation, these methods are often complicated and tedious. This paper introduces a new and simple graphical approach for HEN grassroots design. The new approach based on a single graph called Supply Target Diagram (STD). The ST D is formulated by plotting supply temperatures versus target temperatures of streams . Streams matching can easily be applied in the ST D and splitting of streams is clearly visualized and evaluated. A case study is used to illustrate the application of the new graphical method for grassroots design of HENs.