Yes / This paper investigates the links between institutional systems and the entry mode of Multinational Corporations (MNCs) in developing and transition countries (DTCs). An assessment is made of the reasons for the continuing use of international joint ventures (IJVs) in countries that have undergone reforms intended to lead to the development of wholly owned subsidiaries. The paper argues that formal and informal institutional constraints in DTCs lead to high transaction and uncertainty costs for MNCs, and that the use of IJVs is a rational response to attempt to lower these high costs. The paper follows the literature suggesting that IJVs are normally a `second best¿ entry mode in terms of the potential for foreign direct investment (FDI) to contribute to the development of DTCs. The reform process in Jordan is used to illustrate how institutional systems, especially informal institutional constraints, lead to high transaction and uncertainty costs. In the case of Jordan, this occurred despite a series of four reform packages seeking to reduce the institutional barriers to effective business activities. Interviews of 28 foreign companies provide the basis for an empirical assessment of the importance of both formal and informal institutional constraints and infrastructure problems. The paper includes an outline of a future research agenda that seeks to generalise and develop the results from Jordan to other DTCs.