This document describes a procedure for the identification of single fish and fish fillets to the level of genus or species. The identification of fish species is carried out by PCR amplification of either a segment of the mitochondrial cytochrome b gene (cytb) [1] or the cytochrome c oxidase I gene (cox1@ syn COI) [2]@ [3] or both@ followed by sequencing of the PCR products and subsequent sequence comparison with entries in databases [4]@ [5]. The methodology allows the identification of a large number of commercially important fish species. The decision whether the cytb or cox1 gene segment or both are used for fish identification depends on the declared fish species@ the applicability of the PCR method for the fish species and the availability of comparative sequences in the public databases. This method has been successfully validated on raw fish fillets@ however@ laboratory experience is available that it can also be applied to processed@ e.g. cold smoked@ hot smoked@ salted@ frozen@ cooked@ fried@ deep-fried samples. This document is usually unsuitable for the analysis of highly processed foods@ e.g. tins of fish@ with highly degraded DNA where the fragment lengths are not sufficient for amplification of the targets. Furthermore@ it is not applicable for complex fish products containing mixtures of two or more fish species.