**Our apologies if you receive multiple copies of this CFP** *CALL FOR PAPERS* for the journal track of the European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases (ECML PKDD 2021), Bilbao, Spain. https://2021.ecmlpkdd.org/ *SCOPE AND MOTIVATION* This event is the premier European machine learning and data mining conference. The papers accepted for the journal track will be published in the Machine Learning Journal and the Data Mining and Knowledge Discovery Journal. Papers on all topics related to machine learning, knowledge discovery and data mining are invited. However, given the special nature of the journal track, only papers that satisfy the quality criteria of journal papers and at the same time lend themselves to conference talks will be considered. *IMPORTANT DATES* - ***Continuous Submissions*** are open with cut-off deadlines (January, 31, 2021, May 2, 2021). - Initial Decision: approximately 10 weeks after each cut off date in the submission period. - Notification of Acceptance: revised papers will be re-reviewed. Some accepted papers, especially those that were submitted to the later deadlines, may be included in the ECMLPKDD 2022 special issue. - Conference: 13th to the 17th of September 2021. For more information on submitting a paper to the Journal Track ECML PKDD 2021 please visit https://2021.ecmlpkdd.org/?page_id=1341 *ORGANIZING COMMITTEE* Jose A. Lozano, Basque Center for Applied Mathematics, Spain. Nuria Oliver, Vodafone and Data-Pop Alliance, UK. Fernando Perez-Cruz, Swiss Data Science Center, Switzerland. Stefan Kramer, Johannes Gutenberg Universitat Mainz, Germany. Jeese Read, Ecole Polytechnique, France. Sergio Escalera, Universitat de Barcelona, Spain. Heike Tratmaun, Universitat Munster, Germany. Annalisa Appice, Universita degli Studi di Bari, Italy. Jose A. Gamez, Universidad de Castilla-La Mancha, Spain. Inaki Inza, University of the Basque Country, Spain. Alexander Mendiburu, University of the Basque Country, Spain. Santiago Mazuelas, Basque Center for Applied Mathematics, Spain. Aritz Perez, Basque Center for Applied Mathematics, Spain. Sophie Burkhardt, Johannes Gutenberg Universitat Mainz, Germany. Julia Sidorova, Universidad Complutense de Madrid, Spain. Alipio Jorge, University of Porto, Portugal. Yun Sing Koh, University of Auckland, New Zealand. Tania Cerquitelli, Politecnico di Torino, Italy. Jeronimo Hernandez, Spanish National Research Council, Spain. Zahra Ahmadi, Johannes Gutenberg Universitat Mainz, Germany. We look forward to welcoming you in Bilbao.