ABSTRACT. In this study, the complete mitochondrial genomes of Curetis bulis and Lycaena phlaeas were determined and analyzed. The circular genomes are 15,162 bp long for C. bulis and 15,280 bp long for L. phlaeas, with a total A+T content of 82.6 and 83.1%, respectively. Both mitogenomes contain 37 genes, and their gene orders are similar to those of other lepidopterans. All protein-coding genes (PCGs) are initiated by ATN codons, except for cox1, which is started with the CGA codon; all PCGs terminate in the typical stop codon TAA, except for cox1, cox2, and nad4, which end with a single T. The codons TTA (Leu), ATT (Ile), TTT (Phe), ATA (Met), and AAT (Asn) appear the most frequently. Both of the mitogenome A+T-rich regions harbor the motif ATAGA, followed by a 19-bp Mitochondrial genomes of Curetis bulis and Lycaena phlaeas poly(T) stretch, with C. bulis containing a microsatellite-like (AT) 5 element next to the ATTTA motif, and L. phlaeas containing a microsatellite-like (TA) 6 (AT) element next to the ATTTA motif. The phylogenetic trees of the 17 representative butterfly species, including the two species of this study, were reconstructed with the maximum likelihood and Bayesian inference methods, based on the 13 PCG nucleotide sequence data. The results of the phylogenetic analyses strongly supported the relationships of ((((Lycaenidae + Pieridae) + Nymphalidae) + Hesperiidae) + Papilionidae), which was markedly different from the traditional morphological view of the Lycaenidae and Nymphalidae considered to be sisters of each other.