The Mass Mortality Events (MME-T-MEDNet) dataset compiles information reported on mass mortality events of species in the Mediterranean Sea affecting different organism dwelling in coastal ecosystems. The data compiled in the MME-T-MEDNet dataset was gathered from published scientific papers, grey literature and technical reports using different searching strategies in ISI Web of Knowledge and Google Scholar using different sets of keywords (including those used in Rivetti et al. 2014 and Marba et al. 2015) as well as through contacts with researchers across the Mediterranean. The dataset comprises mass mortality events impacts observed at discrete events generally related to warming episodes across the Mediterranean. The dataset provides information about the year, season, geographic coordinates, protection status of the geographic location, species phylum, species name, the degree of mortality impact, depth range of the mortality and reported biotic and abiotic mortality drivers of the event.