The nineties were a hectic period for many policy makers around the world in respect-of payment systems reforms. The increased attention to payment system issues was brought about by the following trends: (i) increased cross-border competition, innovations, and new communication and information technologies; (ii) the financial and political integration and changing processes in European Union and Countries in Transition. The purpose of this thesis is threefold. Firstly, it seeks to define and critically assess the major payment system developments and problems around the world with a view of advancing the understanding of the payment system matters. Secondly, it presents empirical evidence on payment systems similarities, and differences, across countries. This serves as a basis for recommendations about payment system reforms in Countries in Transition. Thirdly, it emphasises and investigates the institutional aspects of payment systems in different groups of countries. The research finds that payment systems around the world are different, but there are some universal themes and values that can serve as a basis for countries that are reforming their payment systems. The particular recommendations for public policy relate to need for greater: (i) payment system providers and instruments competition; (ii) payment system and monetary policy co-ordination; (iii) emphasis on financial stability