The German Competence Network Malignant Lymphomas (KML) is an initiative of the German Federal Ministry of Education and Research with the goal of establishing a cooperative network between lymphoma study groups to support clinical lymphoma research. The network was initiated in 1999 and comprises 9 national lymphoma study groups. More than 8,600 patients are recruited every year into currently 55 clinical trials by more than 2,400 centers in Germany and Europe. It was the specific aim of the 1st international workshop of the KML (March 6 and 7, 2006) in Cologne to bring together international specialists in the field of lymphoma to discuss current concepts of lymphoma pathogenesis and treatment strategies. This report summarizes novel aspects of pathogenesis and targeted approaches, maintenance therapy, management of the elderly patients, and the use of positron emission tomography for clinical decision making.