The marine microplastic (MMs) is an interdisciplinary problem. The polymer debris are ubiquitous (soil, hydrosphere , atmosphere) and the majority ends, transported by the freshwaters, in the global ocean system: from pelagial waters, surface gyres and benthos up to the animals at different trophic levels . Their quantitative, qualitative and eco-toxicological analyses, based on analytical, physical and chemical methods , are still a challenge due to the complex matrices , materials weathering, limited concentration, and size. Moreover, further fragmentation due to the waves and UV radiation leads to the constant increase of their surface. The aim of this article is to present the advantages, drawbacks and future perspectives of using SEM-EDX method in the analyses of marine polymer debris from macro to the nanoscale . Theoretical issues are presented in comparison to the commonly used approaches. The practical aspects will be discussed based on case studies . Examples of the results, high-resolution SEM pictures are included.