Ciguatera Fish Poisoning (CFP) is a form of ichtyosarcotoxism caused by the consumption of tropical coral reef fishes that have accumulated ciguatoxins (CTXs), neurotoxins produced by dinoflagellates of the genus Gambierdiscus. However, giant clams, frequently consumed in the South Pacific, are sometimes also involved in strong and atypical Ciguatera incidents, as observed in French Polynesia, New Caledonia and Vanuatu. To evaluate the ability of giant clams to accumulate CTXs in their tissues, in vitro contamination experiments were conducted. When fed 10 times per day for up 2 days with 2,000 cells.l -1 (for a total of 40,000 cells.l-1) of a highly toxic strain of Gambierdiscus polynesiensis (containing 7.5 eqv pg P-CTX-3C.cell-1), giant clams appeared toxic by cell based assays (CBA), with a mean of 11.23 eqv ng P-CTX-3C.g-1 wet weight. However, giant clams fed with the same concentration of a non toxic strain of Gambierdiscus toxicus were found non toxic on Neuro-2A cells. When giant clams were fed with lysed cells of G. polynesiensis or G. toxicus, similar results were obtained using CBA. These results will be completed by liquid chromatography mass spectrometry (LC-MS/MS) analysis in order to confirm the identity of the toxins accumulated. These first observations indicate that giant clams are able to fix CTXs and could thus constitute another pathway in the ciguatera food chain. This study should contribute to the improvement of seafood poisoning risk assessment and management programs in ciguateraprone coral reef regions worldwide.