As part of the implementation of the Royal Decree on marine species protection in the Belgian national waters, RBINS has to produce annual reports on observations and strandings of marine mammals in Belgium. Additionally, one of the goals of The Agreement on the Conservation of Small Cetaceans (ASCOBANS) is to develop a national network that makes use of a central stranding and tissue sample database. This database is curated at the Belgian Marine Data Centre and can be accessed on http://www.marinemammals.be for retrieval and data entry of strandings, observations and all necropsies of noteworthy Belgian strandings. The dataset details any intervention steps and assesses the possible cause of death both circumstantially and clinically: 'Natural', 'Bycatch', 'Ship strike', 'Predation' and 'other'. These categorizations have been matched to the P01 BODC/NERC vocabulary. For data management background, see Vandenberghe T., Degraer S., Jauniaux, T., Kerckhof F., Rumes B., Scory S., Haelters J. and Toussaint E. (2016). MarineMammals.be: improving marine mammal stranding, by catch and observation data collection. Bollettino di Geofisica Teorica ed Applicata. 57. 199-200.