The special issue approved by the MuTaLig COST Action CA15135 is available at the link www.frontiersin.org/research-topics/7369/multi-target-directed-ligands-mtdl-as-challenging-research-tools-in-drug-discovery-from-design-to-ph Abstracts can be submitted within January 31 2018 and manuscripts within February 28. Accepted manuscripts co-authored by three different parties within the MuTaLig COST Action can benefit of the open access dissemination budget reserved for this purpose in the second grant period.