The Web services architecture is expected to play a prominent role in developing next generation distributed systems. This chapter discusses how to build dependable systems based on the Web services architecture. More specifically, it surveys base fault tolerance mechanisms, considering both backward and forward error recovery mechanisms, and shows how they are adapted to deal with the specifics of the Web in the light of ongoing work in the area. Existing solutions, targeting the development of dependable composite Web services, may be subdivided into two categories that are respectively related to the specification of Web services composition and to the design of dedicated distributed protocols.