This volume contains the proceedings of the fifthInternational Workshop on Distributed Algorithms (WDAG '91)held in Delphi, Greece, in October 1991. The workshopprovided a forum for researchers and others interested indistributed algorithms, communication networks, anddecentralized systems. The aim was to present recentresearch results, explore directions for future research,and identify common fundamental techniques that serve asbuilding blocks in many distributed algorithms. The volume contains 23 papers selected by the ProgramCommittee from about fifty extended abstracts on the basisof perceived originality and quality and on thematicappropriateness and topical balance. The workshop wasorganizedby the Computer Technology Institute of PatrasUniversity, Greece.