We have reported a new method to detect the geographical origins of unidentified cadavers using BK and JC virus genotyping. Altogether, these two viruses enabled us to determine the geographical origins of more than 70% of unidentified cadavers and to provide much more precise information regarding geographical origin. Recently, we developed a JC virus DNA chip for rapid and simple diagnosis of the geographical origins of unidentified cadavers. The DNA chip takes only half a day to obtain results, whereas the conventional method requires several days. Furthermore, this new technique does not require any special technical knowledge. Herein, we report a newly developed BK virus DNA chip. In addition to the JC virus DNA chip, the BK virus DNA chip may become a powerful tool for the identification of unidentified cadavers.