Mitochondrial (mt) sequences from cytochrome oxidase subunit I to the subunit II gene (COI, COII) were analysed in crustacean talitrid amphipods. Species of the genera Orchestia, Talitrus and Talorchestia from the Mediterranean-East Atlantic area were examined. The expected tRNALeu-UUR gene was not revealed between COI and COII. Instead, a short (35-48 bp) noncoding (NC) AT-rich (ca. 90%) region with putative stem loops was found. Here, we discuss briefly the NC region and explore its potential involvement in generating this novel rearrangement. The COI-NC-COII organization, as well as preliminary phylogenetic results, based on both COI-COII nucleotide and amino-acid sequence indicate monophyly of these talitrid taxa.