The major objective of this paper is to provide an integrative review of the empirical literature on trust in e-commerce in order to contribute to the development of the topic. Although the focus is on empirical findings, first the basic question is addressed why trust is so important in electronic commerce. The analysis centres on conditions of e-commerce transactions that are relevant for the formation of trust problems. Drawing on the theory of information (Hirshleifer and Riley, 1979) two types of uncertainty are described: system-dependent and transaction-specific uncertainty. The different types of uncertainty or risk are also relevant for the understanding of different conceptualtypes of trust which are (often implicitly) investigated in various empiricalstudies. We then provide an overview of research findings that clearly indicates a need for better conceptual trust definitions and make out gaps in knowledge that could be addressed by future research