This special issue contains extended versions of papers presented at FOSSACS-2012, the 15th international conference on Foundations of Software Science and Computational Structures, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2012, Tallinn, Estonia, March 24 - April 1, 2012.

The papers collected in this special issue were invited by the guest editors. The selection was made on the basis of the ranking of the papers by the Program Committee and the opinion of the expert reviewers who assisted the Program Committee. The papers reflect the high level of the conference and represent a wide range of topics. We are grateful to the authors for their excellent submissions.

All papers were refereed in accordance with the usual high standards of LMCS. We are grateful to the members of the Program Committee of FOSSACS 2012 and their subreferees as well as to all those who have served as reviewers of the papers submitted to this special issue.