In this paper, we describe an implementation of a hybrid GA∕IA algorithm (HGA) which combines a Genetic Algorithm (GA) with the Immune Algorithm (IA) for solving multiobjective nonlinear integer programming problems. This proposed method can find better quality Pareto solutions. Moreover, we apply the HGA for solving the optimal design problem of the system reliability as a numerical example of the multiobjective nonlinear integer programming problem. We compare the proposed method with the simple genetic algorithm to verify its effectiveness.