Biomineralized structures can function as a barrier to the external environment, and as such are conceptually entwined with innate immune processes. Disentangling immune and biomineralization mechanisms represents a significant challenge for researchers trying to understand how organisms could integrate biomineral formation and plasticity with maintenance of critical innate immune protection. In fact, there is increasing evidence that immune proteins can serve genuine dual-functional roles, both in regulation of biomineralization, as well as resisting pathogens. This awareness is growing in models as diverse as the dual-functionning haemocytes of marine bivalves, and in mineralization / demineralization of the avian eggshell. Moreover, reef corals, in which calcification is coupled to the photosynthetic activity of their mutualistic symbiots, must adapt their innate immune system to achieve this tolerance. Cnidarian immune-related processes in response to abiotic stresses are increasingly implicated in loss of symbiosis and coral bleaching. This conference aims to bring together scientists working with diverse models of biomineralization, for an exchange of perspectives on the innate immune function of the calcified barrier and the dual role played by specific genes / proteins in these two critical functions.