The complete mitochondrial genome ofHyporhamphus intermediuswas determined to be 16,720 bp in length with (A + T) content of 56.3%, and it consists of 13 protein-coding genes, 22 tRNAs, two ribosomal RNAs, and a control region. The gene composition and the structural arrangement of theH. intermediuscomplete mtDNA were identical to most of the other vertebrates. Interestingly, two tandem repeat units were identified across tRNA-Pro and control region (2 41 bp), while in most of the fishes the tandem repeat units are located in the control region. The molecular data we presented here could play a useful role to study the evolutionary relationships and population genetics of Hemirhamphidae fish. [ABSTRACT FROM AUTHOR]