Investigating inter-organizational cooperation from the perspectives of both partners is important especially when there are interdependencies between the channel partners. The study attempts to accommodate the perspectives of both partners involved in a buyer-supplier relationship and if differences exist between these perspectives, then to understand why these differences exist. The data for this study were collected from buyers responsible for supplier relationships in a Korean telecommunication service provider and from their partners. The results show that switching costs and inter-organizational trust are both significant antecedents of cooperation from the perspective of the buyers, while not significant for the suppliers. Also, the results indicate that technological uncertainty and the fairness of the relationship are significant antecedents from the perspective of the suppliers, and these are not significant for the buyers. In both sample sets, goal consistency significantly affects inter-firm cooperation. The article discusses other findings with important theoretical and practical implications.