This book constitutes the refereed proceedings of the 27th IFIP WG 6.1 International Conference on Formal Techniques for Networked and Distributed Systems, FORTE 2007, held in Tallinn, Estonia, in September 2007 co-located with TestCom/FATES 2007. The 22 revised full papers presented together with 1 invited talk were carefully reviewed and selected from 67 submissions. The papers focus on service oriented computing and architectures using formalized and verified approaches. In addition to the classical protocol specification and verification problems, the issues of composition of protocol functions and of algorithms for distributed systems are addressed. The papers are organized in topical sections on message sequence charts and SDL, concurrency, model programs, theory, verification, model checking, requirements and QoS, as well as components.