We present a restriction site map for the mitochondrial DNA of the gilthead sea bream and the consensus sequence for a region of the mitochondrial cytochrome b gene. Restriction site and nucleotide sequence analysis was used to obtain individual mitotype profiles in a broodstock used for genetic studies. Eight mitotypes were detected among 33 animals assayed. In combination with hypervariable nuclear markers, this variation can be used to identify the parents of any offspring in mass matings and, also, to determine which of the two parents donated the egg and who donated the sperm. On the basis of restriction site variation, the Greek stock analyzed here is very similar to an Israeli stock described in an earlier publication. It is not known if this similarity will hold when the Israeli stock is examined for sequence variation.