An applied-experimental study using Solomon four group design has investigated the effect of social responsibility on Pegah brand preferences. Statistical population encompasses all Pegah customers among governmental offices in Estahban city. Among the customers، 200 individuals are randomly selected and divided equally into four groups. Validity of the questionnaires is examined via face validity approach while reliability is tested using Cronbach's alpha. Findings obtained by 5-fold test methods of Salomon approach showed that brand social responsibility as a whole (encompassing economic، social and environmental dimensions) impacts on brand preferences. Other findings showed that among the dimensions of social responsibility، economic dimension compared to other two has less impact on brand preferences.