The annual international conference on Intelligent Systems for Molecular Biology (ISMB) is the flagship meeting of the International Society for Computational Biology (ISCB). The 2021 conference is the 29th ISMB conference, which has grown to become the world's largest bioinformatics and computational biology conference. Together with the European Conference on Computational Biology (20th Annual Conference) ISMB/ECCB 2021 will be held as a virtual conference due to the ongoing COVID-19 pandemic. ISMB/ECCB 2021 will provide a multidisciplinary forum for disseminating the latest developments in bioinformatics and computational biology. The conference fosters fresh dialogues, collaboration and learning opportunities.