Structural design process is distinguished by the implementation of scientific knowledge and economy to achieve a safe, serviceable, durable, reliable, economical and aesthetically pleasing structure. In complex systems, the need of efficient and economic solutions is essential to produce a feasible and competitive optimum design. Optimum design method forces the designer to identify explicitly a set of design variables, a cost function to be minimized, and a set of constraint functions of the system. Natural systems are noticed to function in a perfect way through the years and to succeed in sustaining life. In this book, the optimum section of simply supported pre-stressed concrete beam is used as an application of developed computer algorithm based on the principles of natural evolution and genetics. The simply supported beam of known basic function is simulated as a species of random origin. The basic function can be described through desired variables like span, imposed dead loads, and live loads. Although concrete strength and type of pre-stressing steel can vary in the same problem, they were treated as a member of the basic function constants.