The ABO blood group system is important in forensic genetics, as well as transfusion medicine. Since the elucidation of the molecular basis of ABO gene regulation, nucleotides of variant alleles or suballeles have been analyzed by polymerase chain reaction (PCR)-based methods and sequencing. Ael (A-elute) is one of the subgroups of A in the ABO system. By analyzing the suballeles responsible for Ael phenotype by PCR-RFLP and PCR direct sequencing, we found seven types of Ael allele. The allele frequency of ABO*Ael in a Japanese population was calculated to be 0.0049.