The development of structural optimization algorithms has helped engineers to a great extent in finding the most suitable structural shape for a particular loading system. However, the common aspect of the optimum shapes obtained in the research works is that they are sometimes unacceptable from a practical point of view, particularly in the case of roof trusses. An effective optimum design method for fixed geometry has been employed to determine the most suitable shape of a root truss among the commonly used ones. The algorithm is efficient and obtains the final design in few iterations which makes the trial type of procedure feasible. After finding the suitable shape, the slope of the upper chord was changed to gain further reduction in the weight. The design method which makes use of the optimality criteria approach was later extended to include the roof slope as design variable. The demonstration of the method was carried out by considering a number of design examples.