Uptake and depuration kinetics of inorganic mercury (Hg) was investigated in the juvenile common cuttlefish Sepia officinalis following exposures via seawater and food using sensitive radiotracer technique (203Hg). The cuttlefish readily concentrated 203Hg when exposed via seawater, with whole body CF > 260 after only 10d of exposure. The total Hg accumulated from seawater was depurated relatively fast with a Tb½ of 17d. During both exposure and depuration periods, accumulated Hg was mainly (> 70%) associated with the muscular parts of the cuttlefish. However, the proportion of the whole body Hg content associated with the digestive gland increased during exposure and depuration phases, suggesting that the metal was transferred from the muscles towards this organ for detoxification. When fed with radiolabelled food, cuttlefish displayed high assimilation efficiency (AE > 90%) and the metal was found to be mainly located in the digestive gland (60% of the whole Hg content). Nevertheless, high depuration rates resulted in short Tb½ (i.e., 4 d), suggesting that this organ has a major role in Hg detoxification and depuration. Whatever the exposure pathway was, low proportion of Hg (< 2%) was found in the cuttlebone. Assessment of the relative contribution of the dietary and dissolved exposure pathways to inorganic Hg bioaccumulation in juvenile cuttlefish revealed that Hg was mainly accumulated from food that contributed for 77 ± 16% of the global metal bioaccumulation.