This book constitutes the thoroughly refereed post-proceedings of the 5th International Workshop on Software Composition, SC 2006, held in Vienna, Austria in March 2006. The workshop has been organized as a satellite event of the European Joint Conferences on Theory and Practice of Software, ETAPS 2006.

The 21 revised full papers presented were carefully selected during two rounds of reviewing and improvement from 60 submissions. The papers reflect current research in software composition to foster developing of composition models and techniques by using aspect-oriented programming, specification of component contracts and protocols, and methods of correct components composition.