Prof. Maria Cristina Fossi, Dr. Cristina Panti and Dr. Matteo Baini, members of the Plastic Busters team, organized the workshop “Marine litter: an emerging cause of concern for marine mammals” during the European Cetacean Society (ECS) conference 2017 in Middelfart, Denmark. The main aim of the workshop was to explore the emerging issue of the impact of marine litter on several marine mammal species, combining a series of presentations focused on current knowledge on the topic, discuss on different methodologies and approaches to face the issue. It represented an opportunity for exchange and discussion to highlight current knowledge gaps.