Almost all aspects of daily life involve plastics, and consequently the production of plastics has increased substantially the last 60 years. Plastics are persistent materials, which tend to accumulate in the marine environment and affect marine life as they remain there for years. The microplastics cause particular problem when ingested by different organisms. Those particles also contain additives such as UV-stabilizers, colourings, flame retardants and plasticizers, which are transported by the particles and are susceptible for uptake and accumulation by living organisms. This workshop aims to discuss several aspects of this ecological threat: i) occurrence of microplastics in the marine environment, ii) microplastics, as vectors of biological and chemical contaminants, iii) impacts of microplastics on the marine life and iv) socioeconomic impacts of microplastics.