This paper is concerned with finding the global optimal solutions for the redundancy optimization problems in series-parallel systems. This study transforms the difficult problem, which is classifed as a nonlinear integer problem, into a 0/1 IP(Integer Programming) by using binary integer variables. And the global optimal solution to this problem can be easily obtained by applying GAMS (General Algebraic Modeling System) to the transformed 0/1 IP. From computational results, we notice that GA(Genetic Algorithm) to this problem, which is known as a best algorithm until now, is very poor in many cases.