This volume constitutes the thoroughly refereed post-proceedings of the Third International Conference on Practice and Theory of Automated Timetabling, PATAT 2000, held in Konstanz, Germany, in August 2000. The 22 revised full papers were carefully selected after two rounds of reviewing and revision. Besides foundational and methodological issues from combinatorics, optimization, evolutionary computing, genetic algorithms, planning, constraints, and searching, a variety of application fields are addressed including course and school timetabling, examination timetabling, employee timetabling,...