The pharmacokinetics of dietary fucoxanthin, one of the xanthophylls in brown sea algae, is little understood. In the present study, mice were orally administered fucoxanthin, and the distribution and accumulation of fucoxanthin and its metabolites fucoxanthinol and amarouciaxanthin A were measured in the plasma, erythrocytes, liver, lung, kidney, heart, spleen and adipose tissue. In a single oral administration of 160 nmol fucoxanthin, fucoxanthinol and amarouciaxanthin A were detectable in all specimens tested in the present study, but fucoxanthin was not. The time at maximum concentration (Tmax) of these metabolites in adipose tissue was 24 h, while the Tmax in the others was 4 h. The area under the curve to infinity (AUC∞) of fucoxanthinol in the liver was the highest value (4680 nmol/g × h) among the tissues tested in the present study, while the AUC∞ of amarouciaxanthin A in adipose tissue was the highest value (4630 nmol/g × h). In daily oral administration of 160 nmol fucoxanthin for 1 week, fucoxanthin was also detectable in the tissues even at a low concentration. The amount of fucoxanthinol was 123 nmol/g in the heart and 85·2 nmol/g in the liver. Amarouciaxanthin A in the adipose tissue was distributed at a concentration of 97·5 nmol/g. These results demonstrate that dietary fucoxanthin accumulates in the heart and liver as fucoxanthinol and in adipose tissue as amarouciaxanthin A.