A novel human leukocyte antigen (HLA)-A allele, HLA-A*3120, was first identified in a National Marrow Donor Program (NMDP) donor. The A*3120 allele resulted from a single nucleotide substitution (T to G) at codon 92 of exon 3 of A*310102. The substitution caused an amino acid change (serine to alanine). This novel allele was also seen in two other unrelated NMDP donors.