The now well-established series of International Colloquia on Theoretical - pects of Computing (ICTAC) brings together practitionersand researchersfrom academia, industry and government to present research results, and exchange experience and ideas. Beyond these scholarly goals, another main purpose is to promote cooperation in research and education between participants and their institutions, from developing and industrial countries. ThisvolumecontainsthepaperspresentedatICTAC2010.Itwasheldduring September 1-3 in the city of Natal, Rio Grande do Norte, Brazil. Therewere68submissionsbyauthorsfrom24countriesallaroundthe world. Each submission was reviewed by at least three, and on average four, Program Committee members and external reviewers. After extensive discussions, they decided to accept the 23 (regular) papers presented here. Authors of a selection of these papers were invited to submit an extended version of their work to a special issue of the Theoretical Computer Science journal. Seven of the papers were part of a special track including one paper on "F- mal Aspects of Software Testing", and six on the "Grand Challenge in Veri?ed Software."
ThespecialtrackwasjointlyorganizedbyMarie-ClaudeGaudel,from the Universit' e de Paris-Sud, and Jim Woodcock, from the University of York.