Chrysomya rufifacies is an ecologically and forensically important blowfly, widespread in Australasia, the Orient and the Americas. The recent molecular studies of Wallman et al. (2005) showed significant levels of nucleotide divergence between Australian populations of this species based on the cytochrome oxidase subunit two (COII) gene, suggesting that Ch. rufifacies is in fact two species. The present study used COII to verify the existence of these two putative species. A 642-bp fragment of COII was sequenced from 37 specimens sampled from 35 diverse Australian geographical locations and analysed using the Kimura-two-parameter distance model and Bayesian methods. Surprisingly, all Ch. rufifacies sequences demonstrated typical levels of mean intraspecific variation (mean = 0.042%, range = 0.000–0.315%, standard error = 0.003) and were resolved as a monophyletic group on the Bayesian tree. Reassessment of the original COII data of Wallman et al. (2005) showed that the high nucleotide divergence within Ch. rufifacies was attributed to two COII sequences actually derived from specimens of Lucilia porphyrina. Ultimately, this study does not support the hypothesis that Australian Ch. rufifacies comprises two cryptic species but instead confirms its existing status as a single taxon.