This paper addresses the possible impact of Web Services in an electronic marketplace setting. The concept of Web Services suggests decentralisation and a business setting relying on automatic transactions. After outlining a Web Service scenario the paper elaborates on the implications on a ‘traditional’ third party situation of electronic commerce transactions. This is illustrated by applying the concept of Web Services to data from a conducted electronic marketplace case study. The conclusion regards a proposition that there still is a need for a trusted third party who acts as a guarantor for the involved actors’ reliability.