Current monitoring of exceptional mortality events of oysters in France consists in passive surveillance, leading to delayed investigation of causation by scientists and management by policy makers. Early detection of clusters of mortality events in time and space would increase possibilities for their investigation and management.A space-time cluster analysis of existing mortality notifications in Pacific oysters was conducted in France, Charente sluices, from 2008 to 2010. As an example of potential demographic confounder of clustering, the analyses were adjusted on oyster age. Several clusters were identified in space and time each studied year. Patterns of mortality notifications were consistent with the introduction and spread of a contagious disease in 2008, which may have become endemic since 2009. Adjustment on oyster age did not change patterns of clusters, suggesting that other variables should be considered in risk factor analyses for mass mortality, either at animal or at environmental level.The routine space-time cluster analysis would be a useful tool to early detect unusual mortality events, with both objectives to improve the epidemiological understanding of the event and to implement timely and efficient control measures. The evolution of the French surveillance strategy from a passive to such a cluster-based surveillance system may be conceivable, if full collaboration of all stakeholders could be achieved