This report consists of two parts The main part contains theories, examples and flowcharts used in the analysis and design of prestressed concrete structures. The design follows Engineering Institute of Thailand (E.I.T. 2534) and American Concrete Institute (ACI 318-99) standards. The supplementary part contains a design aid, which is a program written in Microsoft Excel 200. The program covers the design of beams and slabs based on ACI Standard 318-99. This small supplementary program concept is to allow user to input in a user-friendly way and to provide output, which is easy to read and understand.