This proceedings is the published record of the Thirteenth ACM SIGKDD International Conference on Knowledge Discovery and Data Mining (KDD-07) held in San Jose, California on August 12–15, 2007. The KDD-07 conference provides a forum for novel research results and important applications in the area of data mining and knowledge discovery. The vibrancy, excitement and breadth of the field are reflected by the strong lineup of research papers, invited talks, tutorials and workshops at the conference. The conference and the proceedings represent the efforts of a large number of people. We would like to thank the Industrial and Government Applications Track Chairs, the members of the Organizing Committee, the members of the Program Committee (including the Research Track Senior Program Committee), the external reviewers, and the student volunteers who helped out at the conference. These individuals contributed many hours of their time to serve their scientific community and help make the conference as successful as it is. We would also like to thank the ACM staff and the conference sponsors for their support.