Computer Science Logic (CSL) is the annual conference of the European Association for Computer Science Logic. The conference series started as a programme of International Workshops on Computer Science Logic, and then in its sixth meeting became the Annual Conference of the EACSL. The 15th Annual Conference (and 20th International Workshop), CSL2006, will take place in the week 25 - 29 September 2006; it is organised by the Department of Computer Science, University of Szeged.