TheAnnualConferenceoftheEuropeanAssociationforComputerScienceLogic (EACSL), CSL 2005, was held at the University of Oxford on 22-25 August 2005. The conference series started as a programme of International Workshops onComputerScienceLogic,andtheninits6thmeetingbecametheAnnualC- ference of the EACSL. This conference was the 19th meeting and 14th EACSL conference; it was organized by the Computing Laboratory at the University of Oxford. The CSL 2005 Programme Committee considered 108 submissions from 25 countries during a two-week electronic discussion; each paper was refereed by at least three reviewers. The Committee selected 33 papers for presentation at the conference and publication in these proceedings. The Programme Committee invited lectures from Matthias Baaz, Ulrich Berger, Maarten Marx and Anatol Slissenko; the papers provided by the invited speakers appear at the front of this volume. Instituted in 2005, the Ackermann Award is the EACSL Outstanding D- sertation Award for Logic in Computer Science. The award winners for the - augural year, Mikola j Bojanczyk, ' Konstantin Korovin and Nathan Segerlind, were invited to present their work at the conference.Citations for the awards, abstracts of the theses, and biographical sketches of the award winners are at the end of the proceedings.