In this report we describe a novel HLA-A*34 allele, A*3404, which was initially detected by an unusual serological pattern in two unrelated individuals. Sequencing revealed that the new allele was identical to A*3402 in exons 2 and 3, except for a single nucleotide difference at position 238, changing codon 56 from glycine to arginine. The codon change resulted in positive serological reactions with several sera recognizing A30 and/or A31, implicating an important role for this position in epitope recognition. The allele was identified twice on the haplotype A*3404, B*1402, Cw*0802, DRB1*14, DQB1*05.