~~Abstract— This paper presents a new mathematical model for multi-objective redundancy allocation problems (MORAP). Traditionally, redundancy allocation problem (RAP) consists of two general classes, reliability optimization and availability optimization problems. In availability and reliability classes it is assumed that the entire components are repairable and non-repairable, respectively. In this paper a Mixed Integer Nonlinear Programming (MINLP) model is presented to modeling the problem for availability optimization of a system using both repairable and non-repairable components, simultaneously. To find the solution of proposed MINLP model an efficient Genetic Algorithm (GA) is presented. Furthermore, to show the capability of proposed GA, the MINLP model is solved by using a commercial software package. Experimental results demonstrate that proposed GA result in a better solution compared to commercial software.