The Japanese scad (Decapterus maruadsi) is one of the most commercially important fish species that is popularly harvested in tropical and temperate seas in South East Asian countries. In the present study, we obtained the whole mitochondrial genome sequence of D. maruadsi by overlapped polymerase chain reactions. The entire sequence was 16,541 bp in length, with a gene content (13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes and 2 non-coding regions: the control region and the light strand replication origin) and organization similar to most of the other vertebrates. Overall base composition of the genome was 27.5% of A, 30.2% of C, 25.5% of T and 16.8% of G, showing an obvious anti G bias commonly observed in teleosts. The sequence data of D. maruadsi could provide useful information for the studies on conservation genetics and molecular phylogenetics.