Recently, there is increasing interest in strengthening wholesaler functions and building cooperative relationships between wholesalers and small and medium pharmacy stores in medical supplies channel. Building cooperative relationships between wholesalers and small and medium pharmacy stores is a prior condition to normalize and modernize medical supplies channel. This study tries to understand relationship characteristics and examines the relationships between relationship characteristics and cooperation in medical supplies channel. Drawing from the previous studies, this article identifies relationalisrn, reward power, trust, and dependency as the relationship characteristics and empirically investigates their relationships. The study results confirm that relationship characteristics have significant effects on cooperation and satisfaction. Also cooperation influences satisfaction. Based on these study results, various plans to build cooperative relationships between wholesalers and small and medium pharmacy stores are suggested.