This volume contains a selection of the papers presented at the Sixth Int- national Conference on the Practice and Theory of Automated Timetabling (PATAT) which was organized in Brno, Czech Republic, from August 30 to September 1 of 2006. The PATAT conferences, which are held every 2 years, bring together - searchers and practitioners from across the broad spectrum of inter-disciplinary research activity in search methodologies for automated timetable generation. This includes university timetabling, school timetabling, personnel rostering, transportation timetabling, sports scheduling. The programme of the 2006 c- ference featured 70 presentations which represented the state of the art in au- mated timetabling: there were four plenary papers, 17 full papers, 41 extended abstracts, and eight system demonstrations. After the conference, all authors were invited to submit their papers to a second round of rigorous refereeing for this volume of selected revised papers. We are pleased to have accepted 25 - pers for this volume. This ?gure represents the highest number of acceptances in a PATAT post-proceedings volume and is a testament to the high standards of the papers that were submitted. The organization of the book is structured around particular problem areas.