The European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD) will take place in Bled, Slovenia, from September 7th to 11th, 2009. This event builds upon a very successful series of 19 ECML and 12 PKDD conferences, which have been jointly organized for the past eight years. It has become the major European scientific event in these fields and in 2009 it will comprise presentations of contributed papers and invited speakers, a wide program of workshops and tutorials, a discovery challenge, a demo track and an industrial track.