Managers face with many decision-making problems that affect directly viability of their organization. Group decision-making (GDM) can help the managers to make more accurate decisions. The aim of this paper is to develop a new methodology for GDM problems in an intuitionistic fuzzy environment. In this model, the weights of decision makers are determined by using an extended TOPSIS technique. The individual decisions of decision makers are then converted into the group decision of alternatives. The preference of alternatives is ranked by using an extended TOPSIS technique. Comparisons between the proposed method and other methods are also done in order to show the major technical advances in this model. For the purposes of illustration and verification, a numerical example is presented.