This paper investigates the comparative role of several factors, including information technology (IT), predicting the level of cooperation between two independent organizations. Drawing upon multiple theoretical perspectives, we develop five hypotheses about the impact on interorganizational cooperation of three sets of factors: (1) the characteristics of the environment withm which the relationship operates, (2) the characteristics of the relationship itself, and (3) the characteristics of how IT is used within the relationship. Each of these conceptual constructs is operationalized and measured within the specific context of buyer-supplier relationships in the automobile industry. The hypotheses are tested across two national settings (the US and Japan) using multiple regression analyzes conducted on a data set of 447 distinct relationships. The results indicate that the use of IT and the characteristics of the environment do not play the same role in explaining interorganizational cooperation in the two country settings, while in both countries the characteristics of the relationship significantly contribute to change in 112.