Performance optimization of a single-effect lithium bromide water absorption refrigerationsystem is the subject of this paper. First, the thermodynamic model of the system wasderived based on thefirst and second law analysis of an absorption refrigeration cycle with LiBr-water as the working fluid pair.Then, the effects of different design parameters such as the generator inlet hot water temperature, evaporatorinlet chilling water temperature and absorber and condenser inlet cooling water temperatures on the performanceof the systemwere investigated. In order that, by defining the coefficient of performance (COP), exergyefficiency (Second-law efficiency) and total cost function of the system as the objective functions, the geneticalgorithm optimization technique was implemented to evaluate these performance indexes. Finally, the optimalvalues of design parameters and objective functions were found and compared to the initial values. Resultsshow significant improvement in system COP (about 75 %), exergy efficiency (47 %) and total cost (12 %).