The polymerase chain reaction method was employed to obtain the complete mitochondrial genome of Leiocassis crassilabris from the Yangtze River, China. The mitogenome of L. crassilabris is 16,534 bp in length, consisting of 37 genes coding for 13 proteins, 22 transfer RNAs, 2 ribosomal RNAs, and 1 control region. Its gene arrangement pattern was identical with that of most vertebrates. Overall base composition of mitogenome is estimated to be 31.8% A, 26.9% T, 26.4% C, and 14.9% G, with a high A+T content (58.7%). This is the first report on the complete mitogenome sequence of L. crassilabris, which can provide a basic data for the studies on phylogenetic analysis and conservation genetics.