We report herein the identification of a new HLA-A null allele. This allele, A*0105N, was detected during histocompatibility testing of a cord blood donor and the respective mother. Serologic typing results contrasted those obtained with DNA typing that alone showed the presence of HLA-A*01. ThisA*0105N was due to a nucleotide deletion in exon 4 that altered the reading frame, causing a premature termination.