Transactions between professional vendors and buyers can be governed in a variety of ways ranging from discrete to relational exchange. The literature based upon the relational exchange school posits that as the relationality of exchange increases, norms complement or replace formal contracts as governance mechanisms. Among the numerous governance norms discussed in the relational exchange literature information exchange is often considered to be one of the most important concepts. This paper deals with the information exchange construct and presents empirical results (n = 297) on outcome effects and determinants of suppliers? information exchange behaviour in long-term relationships.