Bioturbating species represent a typical example of ecosystem engineer species in marine benthic environments. These abundant endo- or epibenthic organisms modify the physical structure and geochemical properties of sediments and, at broader ecosystem scales, impact nutrient flows and benthic community structure. The ecological importance of bioturbators depends on (1) their abundance and (2) the magnitude of their bioturbation activity. We suggest that parasitism has a substantial impact on bioturbators, with cascading effects on their role in ecosystem functioning. Reviewing 5940 papers concerning bioturbation and using a set of selective criteria, we identified 176 bioturbating species, with 31% of these potentially parasitized (micro- and macroparasites). However, there are significant discrepancies in the research effort on parasites among bioturbating groups, the highest effort being devoted to molluscs, whereas studies on annelids and arthropods are rare. Furthermore, studies addressing the impacts of parasites on their bioturbating hosts are still scarce, but evidence we do have indicates that parasites impair their hosts’ physiological state, fecundity, behaviour and survival. Because of impacts of parasites on phenotypic traits related to the bioturbation engineering activity of their hosts, parasitism could play a key role on ecosystem functioning through cascade effects. Yet, studies assessing the intricate link between parasites and their hosts’ bioturbation activity, including potential effects on ecosystem functioning, are very scarce.Read less <